View source for 2021 South Korean by-elections

{{refimprove|date=February 2021}}
{{Politics of South Korea}}

The '''2021 South Korean by-elections''' will be held in [[South Korea]] on [[April 7|7 April]] [[2021]].<ref name=":8">{{Cite web|last=공보과|date=2 March 2021|title=4. 7. 재·보궐선거, 서울·부산시장 등 총 21곳 확정|url=https://www.nec.go.kr/site/vt/ex/bbs/View.do?cbIdx=1232&bcIdx=143255&relCbIdx=1090|url-status=live|archive-url=https://web.archive.org/web/20210307081638/https://www.nec.go.kr/site/vt/ex/bbs/View.do?cbIdx=1232&bcIdx=143255&relCbIdx=1090|archive-date=7 March 2021|access-date=7 March 2021|website=[[National Election Commission (South Korea)|National Election Commission]]}}</ref> The [[National Election Commission (South Korea)|National Election Commission]] announced on [[March 2|2 March]] [[2021]] that the by-elections will be held for 21 public offices or electoral districts, including 2 Metropolitan mayors, 2 Municipal mayors, 8 Metropolitan Council constituencies, and 9 Municipal Council constituencies.<ref name=":8" /> Candidate registration must be made from [[March 18]] to [[March 19]], and the list of candidates will be confirmed on [[March 26]].<ref name=":9">{{Cite news|last=임명현|date=2 March 2021|title=4·7재보선, 서울·부산 등 21곳 확정…사전투표는 4월 2~3일|language=ko|work=[[Munhwa Broadcasting Corporation]]|url=https://imnews.imbc.com/news/2021/politics/article/6106117_34866.html|url-status=live}}</ref> 

Voters of the by-elections can vote in advance by [[Early voting]] at 06:00-18:00 [[Korea standard time|KST]] on April 2nd and 3rd.<ref name=":9" /> A early voting place is established for each district or county of the region where the re-election is conducted, and voters can vote at any pre-voting place in the district where the re-election is conducted, regardless of their address.<ref name=":9" /> But, on [[Election day]], voters must vote at their designated polling place and the voting time is from 6 am to 8 pm.<ref name=":9" /> 

In this election, the mayors of [[Seoul]] and [[Busan]], which are the largest city and the second-largest city in the [[South Korea]], are going to be held [[by-election]].<ref name=":10" /> The two major political parties, the [[Democratic Party of Korea|Democratic Party]] and the [[People Power Party (South Korea)|People Power Party]], are concentrating on this by-elections as they believe that the outcome of this election will have a great impact on the [[2022 South Korean presidential election|2022 presidential election]].<ref name=":10" /> [[Democratic Party of Korea|Democratic Party]]'s candidate [[Park Young-sun]] endorsed by [[Kim Jinai]] ([[Open Democratic Party]]) and [[Cho Jung-hun]] ([[Transition Korea|Transtion Korea]]) become the unified candidate of ruling coalition.<ref name=":15" /> On the opposition side, People Power Party's Oh Se-hoon become the unified candidate, endorsed by [[Ahn Cheol-soo]] ([[People Party (South Korea)|People Party]]) and Keum Tae-seop (Independent).<ref name=":16" /> 

== Reasons for by-elections ==
The reasons and offices(constituencies) for by-elections are as follows:<ref name="reasons">{{cite web|last=|first=|date=|title=재보궐선거 실시사유 확정상황|trans-title=Confirmations of the reasons for by-elections|url=http://info.nec.go.kr/main/help/helpMenu.xhtml?selectedName=byelection|url-status=live|archive-url=http://archive.today/j8q8B|archive-date=1 Mar 2021|access-date=15 February 2021|website=Election Statistics System|publisher=[[National Election Commission (South Korea)|National Election Commission]]|language=Korean}}</ref>
=== Metropolitan mayors and governors ===
* '''Mayor of Seoul''': [[Park Won-soon]] ([[Democratic Party of Korea|Democratic]]), Incumbent died.
* '''Mayor of Busan''': [[Oh Keo-don]] ([[Democratic Party of Korea|Democratic]]), Incumbent resigned.

=== Municipal mayors ===
* [[Ulsan]], '''Mayor of Nam District''': Kim Jin-gyu ([[Democratic Party of Korea|Democratic]]), Incumbent was removed from office by judge's ruling.
* [[South Gyeongsang]], '''Mayor of Uiryeong county''': Lee Seon-du ([[People Power Party (South Korea)|People Power]]), Incumbent was removed from office by judge's ruling

=== Members of Metropolitan Council ===
* [[Seoul Metropolitan Council|Seoul]], '''Gangbuk 1st electoral district''' : Kim Dong-sik ([[Democratic Party of Korea|Democratic]]), Incumbent was removed from office by judge's ruling.
* [[:ko:경기도의회|Gyeonggi]], '''Guri 1st electoral district''' : Seo Hyeong-ryeol ([[Democratic Party of Korea|Democratic]]), Incumbent died.
* [[:ko:충청남도의회|North Chungcheong]], '''Boeun at-large electoral district''': Park Jae-wan ([[Independent (politician)|Independent]]), Incumbent resigned.
* [[:ko:전라남도의회|South Jeolla]], '''Suncheon 1st electoral district''': Kim Gi-tae ([[Democratic Party of Korea|Democratic]]), Incumbent died.
* [[:ko:전라남도의회|South Jeolla]], '''Goheung 2nd electoral district''': Park Geum-rae ([[Democratic Party of Korea|Democratic]]), Incumbent died.
* [[:ko:경상남도의회|South Gyeongsang]], '''Goseong 1st electoral district''': Lee Ok-cheol ([[Democratic Party of Korea|Democratic]]), Incumbent was removed from office by judge's ruling.
* [[:ko:경상남도의회|South Gyeongsang]], '''Uiryeong at-large electoral district''': Son Ho-hyeon ([[People Power Party (South Korea)|People Power]]), Incumbent resigned.
* [[:ko:경상남도의회|South Gyeongsang]], '''Hamyang at-large electoral district''': Im Jae-gu ([[People Power Party (South Korea)|People Power]]), Incumbent died.

=== Members of Municipal Council ===
* [[Yeongdeungpo District|Yeongdeungpo]] Council, [[Seoul]] - '''F electoral district''': Heo Hong-seok ([[Democratic Party of Korea|Democratic]]), Incumbent lost his/her right to be elected.
* [[Songpa District|Songpa]] Council, [[Seoul]] - '''D electoral district''': Kim Jang-hwan ([[Democratic Party of Korea|Democratic]]), Incumbent died.
* [[Ulju County|Ulju]] Council, [[Ulsan]] - '''B electoral district''': Park Jeong-ok ([[Democratic Party of Korea|Democratic]]),  Incumbent died.
* [[Paju]] Council, [[Gyeonggi]] - '''A electoral district''': Ahn So-hui ([[Progressive Party (South Korea, 2017)|Progressive]]), Incumbent lost his/her right to be elected.
* [[Yesan County|Yesan]] Council, [[South Chungcheong]] - '''D electoral district''': Yu Yeong-bae ([[국민의힘|People Power]]), Incumbent was removed from office by judge's ruling.
* [[Gimje]] Council, [[North Jeolla]] - '''B electoral district''': On Ju-hyeon ([[Independent politician|Independent]]), Incumbent resigned.
* [[Boseong County|Boseong]] Council, [[South Jeolla]] - '''C electoral district''': Chung Gwang-sik ([[Democratic Party of Korea|Democratic]]), Incumbent lost his/her right to be elected.
*[[Uiryeong County|Uiryeong]] Council, [[South Gyeongsang]] - '''D''' '''electoral district''': Son Tae-yeong ([[국민의힘|People Power]]), Incumbent resigned.
* [[Haman County|Haman]] Council, [[South Gyeongsang]] - '''C electoral district''': Kim Jeong-seon ([[국민의힘|People Power]]), Incumbent lost his/her right to be elected.

== Issues ==
=== Amendment of Democratic Party's constitution ===
The Democratic Party’s constitution states that it cannot nominate any by-election candidates if the party caused the situation that made the by-election necessary. The Democratic Party held a vote on {{Dts|Nov 2, 2020}} to their members on amending the party's constitution and almost 87 percent voted in favor of the change. The main opposition party, People Power Party, criticized the Democratic Party’s decision, accusing it of revictimizing the women who were allegedly sexually harassed by the late mayor and former mayor. People Power Party interim leader Kim Jong-in said “President Moon is trying to reverse the so-called ‘Moon Jae-in article,’ which was created while he was the party leader", calling on the president to publicly take a position on the envisioned revision of the party rules.<ref>{{Cite news|last=Kim|first=So-hyun|date=2 November 2020|title=Opposition slams ruling party for fielding Seoul, Busan mayoral candidates|work=[[The Korea Herald]]|url=http://www.koreaherald.com/view.php?ud=20201102000887|url-status=live|access-date=18 February 2021}}</ref>
=== Resignation of Yoon Seok-youl ===
[[File:윤석열 검찰총장.png|thumb|150px|{{Center|43rd Prosecutor General of South Korea<br>'''Yoon Seok-youl'''}}]]
The ruling [[Democratic Party of Korea|Democratic Party]] have been speeding up the creation of a new investigative agency to weaken the power of the prosecution service.<ref name="Resignation of Yoon 2">{{cite news |title=Taking investigative power from prosecutors inconsistent with Constitution: top prosecutor |url=http://www.koreatimes.co.kr/www/nation/2021/03/113_304858.html |access-date=21 March 2021 |work=[[The Korea Times]] |agency=[[Yonhap News Agency]] |date=2 March 2021}}</ref> This move was followed by the establishment of [[Corruption Investigation Office for High-ranking Officials]].<ref name="Resignation of Yoon 2" /> [[Yoon Seok-youl]], who had clashed with the Moon administration and Democratic Party,<ref>{{bulleted list
|{{cite news |last1=Ser |first1=Myo-ja |last2=Heo |first2=Jin |title=Ruling party takes aim at Prosecutor General Yoon |url=https://koreajoongangdaily.joins.com/2021/01/26/national/politics/Yoon-Seokyoul-poll/20210126192506908.html |access-date=23 March 2021 |work=[[Korea JoongAng Daily]] |date=26 January 2021}}
|{{cite news |last1=Lim |first1=Jae-woo |title=Prosecutor general says he is not an “underling” of the justice minister |url=http://english.hani.co.kr/arti/english_edition/e_national/967024.html |access-date=23 March 2021 |work=[[The Hankyoreh]] |date=23 October 2020}}
|{{cite news |last1=Ser |first1=Myo-ja |title=Reshuffle dismantles prosecutor general’s team, probes ofbulleted list Blue House |url=https://koreajoongangdaily.joins.com/news/article/article.aspx?aid=3072419 |access-date=21 March 2021 |work=[[Korea JoongAng Daily]] |date=9 January 2020}}
| }}</ref> publicly opposed the idea of separating powers of investigation and prosecution.<ref>{{Cite news|date=3 March 2021|title=Top Prosecutor Denounces Gov't Plans to Create New Investigative Agency|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Dm&Seq_Code=159915|url-status=live|access-date=23 March 2021}}</ref> [[Ministry of Justice (South Korea)|Minister of Justice]] [[Park Beom-kye]] said he will gather various opinions from members of the prosecution on establishing an agency that would handle serious crimes.<ref>{{Cite news|date=2 March 2021|title=Justice Minister Will Heed Prosecution's Views on Proposed New Agency|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Dm&Seq_Code=159885|url-status=live|access-date=23 March 2021}}</ref> On 4 March 2021, [[Prosecutor General of South Korea|Prosecutor General]] [[Yoon Seok-youl]] announced his resignation in front of the [[Supreme Prosecutors' Office of the Republic of Korea|Supreme Prosecutors' Office]] in protest against the government's push to weaken the power of the prosecution service.<ref name="Resignation of Yoon1">{{cite news|last1=Shin|first1=Ji-hye|date=4 March 2021|title=Top prosecutor resigns in defiance of weakening prosecution’s power|work=[[The Korea Herald]]|url=http://www.koreaherald.com/view.php?ud=20210304000866&ACE_SEARCH=1|access-date=21 March 2021}}</ref> On the same day, [[President of South Korea|President]] [[Moon Jae-in]] accepted the resignation.<ref>{{cite news|date=4 March 2021|title=Moon Accepts Prosecutor General Yoon's Intent to Resign|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=159941|url-status=live|access-date=23 March 2021}}</ref>

[[Prime Minister of South Korea|Prime Minister]] [[Chung Sye-kyun]] has expressed regret over the resignation.<ref>{{Cite news|date=4 March 2021|title=PM Regrets Top Prosecutor's Resignation|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=159938|url-status=live}}</ref> The main opposition [[People Power Party (South Korea)|People Power Party]]'s interim leader [[Kim Chong-in]] said he would meet with Yoon if he wants to.<ref name="Resignation of Yoon 3">{{cite news |last1=Kim |first1=So-hyun |title=[Newsmaker] Political circles eye on Yoon’s next move |url=http://www.koreaherald.com/view.php?ud=20210305000782&ACE_SEARCH=1 |access-date=21 March 2021 |work=[[The Korea Herald]] |date=5 March 2021}}</ref> On the other hand, leader of the [[Democratic Party of Korea|Democratic Party]] [[Lee Nak-yon]] has criticized Yoon, saying his resignation "out of the blue" was absurd for a public official.<ref name="Resignation of Yoon 3" /> But, [[Democratic Party of Korea|Democratic Party]]'s approval rating plunged to a record low since the 2017 inauguration of the [[Moon Jae-in]] government. Gallup Korea said the decrease in the [[Democratic Party of Korea|Democratic Party]]'s approval rating apparently came with its recent conflict with former [[Prosecutor General of South Korea|Prosecutor General]] [[Yoon Seok-youl]] over creating a new investigative agency to take over the prosecution's investigative powers.<ref>{{cite news |title=DP's approval rating plunges to record low since Moon took office |url=http://www.koreaherald.com/view.php?ud=20210305000790&ACE_SEARCH=1 |access-date=21 March 2021 |work=[[The Korea Herald]] |agency=[[Yonhap News Agency]] |date=5 March 2021}}</ref> Public support for Yoon Seok-youl rose sharply to take the lead over other potential presidential candidates in South Korea.<ref>{{cite news |title=Yoon Seok-youl's support rate shoots up after resignation to lead polls on presidential race |url=http://www.koreaherald.com/view.php?ud=20210308000268&ACE_SEARCH=1 |access-date=21 March 2021 |work=[[The Korea Herald]] |agency=[[Yonhap News Agency]] |date=8 March 2021}}</ref> Some political critics analyzed that [[Yoon Seok-youl]] became a big variable in the 2021 by-elections.<ref>{{cite news |title=4·7 보선 최대 변수 떠오른 ‘윤석열의 입’…‘한마디 정치’로도 영향 |url=https://www.donga.com/news/Politics/article/all/20210305/105737212/1 |access-date=21 March 2021 |work=[[Dong-a Ilbo]] |agency=[[News1]] |date=5 March 2021 |language=ko}}</ref>
===LH scandal===
A property speculation scandal involving employees in South Korea’s top housing agency, the [[Korea Land & Housing Corporation]] (LH), emerged in March 2021, becoming a factor in the by-elections.<ref>{{cite news|last=Cha|first=Sangmi|date=5 March 2021|title=South Korea roiled by property scandal amid soaring house prices|language=en|work=|agency=[[Reuters]]|url=http://reuters.com/article/us-southkorea-property/south-korea-roiled-by-property-scandal-amid-soaring-house-prices-idUSKBN2B10QZ|url-status=live|access-date=4 April 2021|quote=Accusations that officials at South Korea’s state housing corporation tried to use insider information to cash in on runaway property prices has thrown new fuel on an issue that is draining support from the ruling party ahead of key elections.}}</ref> The scandal involved 20 LH workers allegedly acting on insider information to buy undeveloped farmland near a new town development project in the Seoul region since April 2018, before the announcement of the project. There was public uproar as the scandal emerged amidst an ongoing housing affordability crisis in South Korea. Median apartment prices in Seoul have soared nearly 60% since President Moon came into office in May 2017, despite repeated property price cooling measures implemented by the Moon administration.<ref name=":14">{{cite news|last=Cha|first=Sangmi|date=5 March 2021|title=South Korea roiled by property scandal amid soaring house prices|language=en|work=|agency=[[Reuters]]|url=http://reuters.com/article/us-southkorea-property/south-korea-roiled-by-property-scandal-amid-soaring-house-prices-idUSKBN2B10QZ|url-status=live|access-date=4 April 2021|quote=Median apartment prices in Seoul - where about a fifth of South Koreans live - have soared nearly 60% since May 2017 when Moon came into office, despite repeated government interventions to try to cool down the market.}}</ref> As a result, President Moon's approval ratings sank to 34%, the lowest approval rating of his term after the scandal emerged along with the administration's clash with the prosecution.<ref>{{cite news|date=23 March 2021|title=Moon, ruling party face crisis as their ratings plummet|language=en|work=Noh Hyun-woong|agency=[[The Hankyoreh]]|url=http://www.hani.co.kr/arti/english_edition/e_national/987912.html|access-date=4 April 2021}}</ref><ref>{{cite news |title=Land Speculation Scandal Grips South Korea |url=https://thediplomat.com/2021/03/land-speculation-scandal-grips-south-korea/ |access-date=4 April 2021 |work=Jenna Gibson |agency=[[The Diplomat]] |date=26 March 2021 |language=en}}</ref>

== Mayor of Seoul ==
{{Infobox election
| election_name = 2021 Seoul mayoral by-election
| type = By-election
| country = South Korea
| seats_for_election = [[Mayor of Seoul|Seoul Metropolitan Mayor]].<br />Elected by simple majority using [[first past the post]].<br />Triggered by death of incumbent
| ongoing = yes
| previous_election = 2018 South Korean local elections#Seoul
| previous_year = 2018
| next_election = 2022 South Korean local elections
| next_year = 2022
| election_date = {{Start date|2021|04|07|df= y}}
 <!-- Democratic Party -->| candidate1 = [[Park Young-sun]]
| image1 = [[File:20210128 박영선 시사타파MBN인터뷰.JPG|160px]]
| party1 = Democratic Party of Korea
| alliance1 =  {{Collapsible list|framestyle=border:none; padding:0;|bullets=true|title=Ruling coalition|1=[[Open Democratic Party]] |2=[[Transition Korea]]}}
| last_election1 = -
| popular_vote1 = -
| percentage1 = -
  <!-- People Power Party -->| candidate2 = [[Oh Se-hoon]]
| image2 = [[File:Oh Se-Hoon.jpg|160px]]
| party2 = People Power Party (South Korea)
| alliance2 = {{Collapsible list|framestyle=border:none; padding:0;|bullets=true|title=Opposition coalition|1=[[People Party (South Korea)|People Party]] |2=Keum Tae-seop (Ind.)}}
| last_election2 = -
| popular_vote2 = -
| percentage2 = -
| title = Mayor of Seoul
| posttitle = Subsequent Mayor of Seoul
| before_election = [[Park Won-sun]]
| before_party = Democratic Party of Korea
| after_election = 
| after_party = 
| map_image = 
| map_size = 
| map_alt = 
| map = 
| map_caption = 
| flag_image = File:Flag of Seoul.svg
}}{{See also|Mayor of Seoul}}

=== Background ===

==== Death of Park Won-soon ====
{{POV section|date=February 2021}}
The death of Park Won-soon, the mayor of the largest city in [[South Korea]], was hugely impactful on the 2021 By-Elections.<ref name=":3">{{Cite web|date=2020-07-10|title=[사설] 충격과 안타까움 안긴 박원순 시장의 죽음|url=http://www.hani.co.kr/arti/opinion/editorial/953189.html|access-date=2021-02-20|website=www.hani.co.kr|language=ko}}</ref> This was even more shocking to South Koreans in that he was the person who had been fighting for [[women's rights]].<ref name=":3" /><ref name=":4">{{Cite web|title=시민운동가에서 3선 서울시장까지…파란만장 삶|url=https://news.kbs.co.kr/news/view.do?ncd=4491007|access-date=2021-02-20|website=KBS 뉴스|language=ko}}</ref> He fought against authoritarian rule in South Korea and was put in prison in the 1970's as a college student.<ref name=":4" /> After becoming a lawyer, he took on many cases related to [[women's rights]]. It was his well-known{{cn|date = February 2021}} achievement that he won South Korea's first [[sexual harassment]] case.<ref>{{Cite web|title=국내 첫 성희롱 소송 변호인, 그가 박원순이었다|url=https://www.chosun.com/site/data/html_dir/2020/07/09/2020070904382.html|access-date=2021-02-20|website=www.chosun.com|language=ko}}</ref> So, it was shock that the person who had been fighting for women rights committed suicide after his female employee accused him of sexual harassment.<ref>{{Cite news|last=Bicker|first=Laura|date=10 July 2020|title=Park Won-soon: Mayor of Seoul found dead after going missing|work=[[BBC News]]|url=https://www.bbc.com/news/53346831|url-status=live|access-date=16 February 2021}}</ref>

==== Increased attention of female candidates ====
{{Original research|date=February 2021}}
Because of the sexual harassment incidents of incumbent mayors, each political party paid attention to female candidates.<ref>{{Cite web|date=2020-12-27|title=[보궐선거 D-100일] 여성 광역단체장 0명…이번엔 '성평등' 바람 불까요?|url=http://www.hani.co.kr/arti/politics/assembly/976074.html|access-date=2021-02-20|website=www.hani.co.kr|language=ko}}</ref> In December 2020, the majority of the potential candidates in [[Seoul]] are women, showing the rival parties' bid to promote themselves as women-friendly.<ref name=":5" /> Three women ([[Na Kyung-won]], [[Cho Eun-hee]] and [[Lee Hye-hoon]]) from the main opposition [[People Power Party (South Korea)|People Power Party]] have announced their Seoul mayoral bids.  The possible female candidates from the [[Democratic Party of Korea|Democratic]] side are [[Ministry of SMEs and Startups|Minister of SMEs and Startups]] [[Park Young-sun]] and [[Anti-Corruption and Civil Rights Commission|Anti-Corruption and Civil Rights Commission Chairwoman]] [[Jeon Hyun-hee]].<ref name=":5">{{Cite news|last=Yi|first=Whan-woo|date=5 December 2020|title=Parties gearing up for Seoul, Busan by-elections|work=[[The Korea Times]]|url=https://www.koreatimes.co.kr/www/nation/2020/12/356_300322.html|url-status=live|access-date=18 February 2021}}</ref> In addition, political parties are considering adding or increasing women's additional points to the primary rules. The Democratic Party maintained the existing 10-25% of the women's additional point, and the People Power Party decided to reflect the women's additional points at 10% in the main primary race and 20% in the preliminary primary race.<ref>{{Cite news|last1=정환봉|last2=장나래|date=8 February 2021|title=4·7 보선 여야 경선룰 확정…여성가산점, 여당은 유지 야당은 축소|language=Korean|work=[[The Hankyoreh]]|url=http://www.hani.co.kr/arti/politics/assembly/977949.html|url-status=live|access-date=18 February 2021}}</ref>

==== Connection between 2011 by-election and 2021 by-election ====
In 2011, [[South Korea]] held a by-election to fill vacant [[Mayor of Seoul|Seoul Mayor]]. Mayor [[Oh Se-hoon]] who was incumbent from 2006 to 2011 staked his mayoralty on [[2011 Seoul free lunch referendum|Seoul free lunch referendum]]. [[Oh Se-hoon]] opposed to give free meals to all children, insisting that free lunch policy is "populism",<ref>{{cite news |last1=김경욱; 이경미 |title=귀막은 오세훈 "무상급식, 망국적 포퓰리즘" |url=http://www.hani.co.kr/arti/area/area_general/452034.html |access-date=18 February 2021 |work=[[The Hankyoreh]] |date=3 December 2010|language=Korean}}</ref><ref>{{cite news |last1=심언기 |title=오세훈 "무상급식은 포퓰리즘의 첫 단추였다" |url=https://www.news1.kr/articles/?2485081 |access-date=18 February 2021 |work=[[News1]] |date=11 November 2015|language=Korean}}</ref> and promised that he will resign if the outcome of referendum is not in favor of his 'selective' policy. However, the referendum which turnout have to be exceed one third of electorate was invalidated by low turnout. Eventually, Mayor Oh resigned on 26 August 2011 as promised and [[2011 South Korean by-elections]] were held in [[Seoul]] for his replacement.<ref>{{cite news |title=Seoul Mayor Steps Down After Losing School Lunch Referendum |url=https://www.voanews.com/east-asia/seoul-mayor-steps-down-after-losing-school-lunch-referendum |access-date=18 February 2021 |work=[[Voice of America]] |date=25 August 2011}}</ref>

[[Park Won-soon]], who become [[Mayor of Seoul]] for [[Oh Se-hoon]]'s replacement, had started as the underdog at the early phase. Then, Independent frontline runner [[Ahn Cheol-soo]] who had been a strong supporter of Park Won-soon's famous civic group endorsed him for [[Mayor of Seoul|Seoul Mayor]].<ref>{{cite news |last1=장은교 |title=박원순·안철수 '동지적 관계'서 이젠 경쟁자로 |url=http://news.khan.co.kr/kh_news/khan_art_view.html?art_id=201109052209105 |access-date=18 February 2021 |work=[[Kyunghyang Shinmun]] |date=5 September 2011}}</ref><ref>{{cite news |last1=류지복 |title=안철수 지지율 박원순으로 옮겨갈까 |url=https://www.yna.co.kr/view/AKR20110906158400001 |access-date=18 February 2021 |work=[[Yonhap News Agency]] |date=6 September 2011}}</ref> Thanks to the support of [[Ahn Cheol-soo]], [[Park Won-soon]] overtaken [[Na Kyung-won]], the frontline runner of the ruling [[Grand National Party]], in a poll.<ref>{{cite news |last1=신지홍; 심인성; 이준서 |title=박원순, 나경원에 7∼18%P 앞서 |url=https://www.hankyung.com/politics/article/2011092346698 |access-date=18 February 2021 |work=[[Korea Economic Daily]] |date=23 September 2011}}</ref>

On 27 September 2011, [[Na Kyung-won]] who worked as the [[Grand National Party|GNP]]’s spokeswoman from 2006 to 2008 was nominated as the [[Grand National Party|GNP]] candidate.<ref>{{cite news |last1=황철환 |title=한나라당, 나경원 서울시장 후보 확정 |url=https://www.yna.co.kr/view/AKR20110927215800001 |access-date=18 February 2021 |work=[[Yonhap News Agency]] |date=27 September 2021}}</ref><ref>{{cite news |last1=Moon |first1=Kyu-toi |title=The Meaning of Seoul's Election |url=https://thediplomat.com/2011/11/the-meaning-of-seouls-election/ |access-date=18 February 2021 |work=[[The Diplomat]] |date=7 November 2011}}</ref> Meanwhile, the opposition coalition unified the candidate. Independent candidate [[Park Won-soon]], Democratic candidate [[Park Young-sun]] and Democratic Labor candidate [[Choi Gyu-yeop]] participated in the candidate unification primary, and [[Park Won-soon]] won the primary and became the nominee of the opposition coalition.<ref>{{cite news |last1=장윤선; 이경태 |title=박원순, 야권 서울시장 단일후보로 확정 "10월 26일 새 시대의 첫 차 타고 떠날 것" 국민참여경선 투표율 59.59% '흥행 대박' |url=http://www.ohmynews.com/NWS_Web/View/at_pg.aspx?CNTN_CD=A0001635079&PAGE_CD=N0000&BLCK_NO=3&CMPT_CD=M0001 |access-date=18 February 2021 |work=[[Oh My News]] |date=3 October 2011}}</ref> On 26 October 2011, [[Park Won-soon]] was elected by 7.19%, winning 53.40% of the votes. On the other hand, [[Na Kyung-won]] won 46.21% of the votes and become second place.<ref>{{Cite news|last=박종찬|date=26 October 2011|title=[27일 2시19분 최종] 박원순 후보 53.40%로 당선 확정|work=[[The Hankyoreh]]|url=http://www.hani.co.kr/arti/politics/politics_general/502660.html|url-status=live}}</ref> So, there is a saying that it is similar to the [[2011 South Korean by-elections|2011 by-election]] in that [[Park Young-sun]], [[Na Kyung-won|Na kyung-won]], [[Oh Se-hoon]], and [[Ahn Cheol-soo|Ahn Chul-soo]], who were involved in the 2011 mayoral by-election, are running for the Seoul mayoral by-election in 2021.<ref>{{Cite news|last=류호; 박서영|date=2021-02-13|title=어게인 2011년? 어디서 본 것 같은 서울시장 선거|language=ko|work=[[Hankook Ilbo]]|url=https://www.hankookilbo.com/News/Read/A2021020915120001222|url-status=live}}</ref>

=== Registered candidates ===
{| class="wikitable" style="font-size:90%;"
|+
!#
!Party
!Name
!Date of birth
!Career
!Property<br/>{{Small|([[Korean won|KRW]], thousand)}}
!Tax payment<br/>{{Small|([[Korean won|KRW]], thousand)}}
!style="width: 12em"|Criminal record
!Note
|-
| style="text-align:center;" |'''1'''
|[[Democratic Party of Korea]]
|[[Park Young-sun]]
| style="text-align:center;"|{{DTS|1960-01-22}} (age {{Age|1960|1|22}})
|Fmr. [[Ministry of SMEs and Startups|Minister of SMEs and Startups]]<br/>Fmr. Memeber of the [[National Assembly (South Korea)|National Assembly]] (2004-2020)
| style="text-align:right;" |5,669,123
| style="text-align:right;" |1,115,967
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''2'''
|[[People Power Party (South Korea)|People Power Party]]
|[[Oh Se-hoon]]
| style="text-align:center;"|{{DTS|1961-01-04}} (age {{Age|1961|1|4}})
|Fmr. [[Mayor of Seoul]] (2006-2011)<br>Fmr. Member of the [[National Assembly (South Korea)|National Assembly]] (2000-2004)
| style="text-align:right;" |5,934,143
| style="text-align:right;" |209,692
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''{{strikethrough|4}}'''
|{{strikethrough|[[People Party (South Korea)|People Party]]}}
|{{strikethrough|[[Ahn Cheol-soo]]}}
| style="text-align:center;"|{{strikethrough|{{DTS|1962-01-22}} (age {{Age|1962|1|22}})}}
|
|
|
|
|Resigned
|-
| style="text-align:center;" |'''6'''
|[[Basic Income Party]]
|Shin Ji-hye
| style="text-align:center;"|{{DTS|1987-10-22}} (age {{Age|1987|10|22}})
|Standing Leader of the [[Basic Income Party]]<br>Fmr. Teacher of the Poidong Inyeon Study
| style="text-align:right;" |77,709
| style="text-align:right;" |27,779
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''7'''
|[[National Revolutionary Dividends Party|National Revolutionary Party]]
|[[Huh Kyung-young|Heo Kyung-young]]
| style="text-align:center;"|{{DTS|1947-07-13}} (age {{Age|1947|7|13}})
|Fmr. South Korean Presidential Candidate (1997 & 2007)<br>Honorary President of the [[National Revolutionary Dividends Party|National Revolutionary Party]]
| style="text-align:right;" |7,262,241
| style="text-align:right;" |1,907,142
| style="text-align:center;"|{{Collapsible list|framestyle=border:none; padding:0;|title_style=text-align: center|bullets=true|title=3 records|1=Traffic Accident Handling Special Act (1,000,000\) |2=Traffic Accident Handling Special Act/Road and Traffic Act (2,000,000\) |3=Defamation/Public Offical Election Act (1yr 6mths)}}
|
|-
| style="text-align:center;" |'''8'''
|[[Mirae Party]]
|Oh Tae-yang
| style="text-align:center;"|{{DTS|1975-10-26}} (age {{Age|1975|10|26}})
|Leader of the [[Mirae Party]]<br>Fmr. Secretary-General of the Youth Party
| style="text-align:right;" |0
| style="text-align:right;" |159
| style="text-align:center;"|{{Collapsible list|framestyle=border:none; padding:0;|title_style=text-align: center|bullets=true|title=1 record|1=Military Service Act (1yr 6mths)}}
|
|-
| style="text-align:center;" |'''9'''
|[[Minsaeng Party]]
|Lee Su-bong
| style="text-align:center;"|{{DTS|1961-06-23}} (age {{Age|1961|6|23}})
|Interim Leader of the [[Minsaeng Party]] (ERC)<br>Fmr. Director of the Policy Institute of the [[Korean Confederation of Trade Unions|KCTU]]
| style="text-align:right;" |318,000
| style="text-align:right;" |2,110
| style="text-align:center;"|{{Collapsible list|framestyle=border:none; padding:0;|title_style=text-align: center|bullets=true|title=1 record|1=Assembly and Demonstration Act (1yr)}}
|
|-
| style="text-align:center;" |'''10'''
|New United Liberal Democrats
|Bae Yeong-gyu
| style="text-align:center;"|{{DTS|1961-02-25}} (age {{Age|1961|2|25}})
|Fmr. Chairman of the Sambu Construction<br>Legal Consultant of the Samsung Insurance
| style="text-align:right;" |10,000
| style="text-align:right;" |4,446
| style="text-align:center;"|{{Collapsible list|framestyle=border:none; padding:0;|title_style=text-align: center|bullets=true|title=5 records|1=Real Estate Registration Sepcial Measure Act (2,000,000\)|2=Trademark Act (1,000,000\)|3=Perjury (2,000,000\)|4=False accusation/Act on the registration of real right holder of  real estate (8yrs, 2yrs of probat.)|5=Fraud (1yr, 2yrs of probat.)}}
|
|-
| style="text-align:center;" |'''11'''
|[[Women's Party (South Korea)|Women's Party]]
|Kim Jin-ah
| style="text-align:center;"|{{DTS|1975-08-01}} (age {{Age|1975|8|1}})
|Fmr. Creative Director of the Innocean Worldwide<br>Writer of "I'm just looking for my pie, I'm not here to save humanity"
| style="text-align:right;" |245,100
| style="text-align:right;" |7,803
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''12'''
|[[Progressive Party (South Korea, 2017)|Progressive Party]]
|Song Myeong-suk
| style="text-align:center;"|{{DTS|1987-01-23}} (age {{Age|1987|1|23}})
|Co-Leader of the Progressive Party<br>Director of the Central Training Institute of the Progressive Party
| style="text-align:right;" | -7,118
| style="text-align:right;" |301
| style="text-align:center;"|{{Collapsible list|framestyle=border:none; padding:0;|title_style=text-align: center|bullets=true|title=1 record|1=General traffic obstruction/Assembly and Demonstration Act (1,000,000\)}}
|
|-
| style="text-align:center;" |'''13'''
|[[Independent politician|Independent]]
|Chung Dong-hui
| style="text-align:center;"|{{DTS|1968-09-08}} (age {{Age|1968|9|8}})
|Writer of "Seoul Mayor, 12 Stars", "3 o'clock Korea" etc.<br>Fmr. Candidate for South Korean National Assembly in Gangnam I (2020)
| style="text-align:right;" |2,327,306
| style="text-align:right;" |307,760
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''14'''
|[[Independent politician|Independent]]
|Lee Do-yeop
| style="text-align:center;"|{{DTS|1984-06-14}} (age {{Age|1984|6|14}})
|Military Interpreter at [[Korean Augmentation To the United States Army]] (Sergeant)<br>Writer of "Jyushinji"
| style="text-align:right;" |112,900
| style="text-align:right;" |0
| style="text-align:center;"|None
|
|-
| style="text-align:center;" |'''15'''
|[[Independent politician|Independent]]
|Shin Ji-ye
| style="text-align:center;"|{{DTS|1990-06-20}} (age {{Age|1990|6|20}})
|Leader of the Korean Women's Political Network<br>Fmr. Green Party Candidate for Seoul Mayor (2018)
| style="text-align:right;" |0
| style="text-align:right;" |3,473
| style="text-align:center;"|None
|
|-
! colspan="9" |Source: [http://info.nec.go.kr/main/showDocument.xhtml?electionId=0020210407&topMenuId=CP&secondMenuId=CPRI03 National Election Commission]
|}

==== Candidate unification ====
<div><ul style="float:right;"> <!-- The <div><ul><li> code displays tables side by side when window width allows it -->
<li style="display: inline-table;">
{| class=wikitable style="font-size:90%; text-align:center;"
|-
! colspan=2 |[[File:Democratic Party of Korea, Symbol application 3.svg|65x65px|center|link=Democratic Party of Korea]]<big>Democratic Party Ticket</big>
|-
! style="font-size:135%; color:white; background:{{Democratic Party of Korea/meta/color}}"|Park Young-sun
|-style="font-size:100%; color:black; background:#c8ebff"
| '''''for Mayor'''''
|-<--Do not add a generic image here, that would be forbidden under WP:IPH-->
|[[File:20210128 박영선 시사타파MBN인터뷰.JPG|center|200x200px]]
|-
| style=width:16em|2nd<br>[[Ministry of SMEs and Startups|Minister of SMEs and Startups]]<br>(2019-2021)
|-
| '''Supported by'''
|-
|[[Kim Jinai|Kim Jin-ae]] ([[Open Democratic Party|Open Democratic]])<br>[[Cho Jung-hun]] ([[Transition Korea]])
|-
|[http://www.pys21.net/ '''Campaign''']
|-
|[[File:Campaign_logo_of_Park_Young-sun(박영선)_for_Mayor_of_Seoul.png|center|200x100px]]
|} </li>
<li style="display: inline-table;">
{| class=wikitable style="font-size:90%; text-align:center;"
|-
! colspan=2 |[[File:People Power Party (South Korea), signature 1.svg|65x65px|center|link=People Power Party (South Korea)]]<big>People Power Party Ticket</big>
|-
! style="font-size:135%; color:white; background:{{People Power Party (South Korea)/meta/color}}"|Oh Se-hoon
|-style="font-size:100%; color:black; background:rgba(230, 30, 43, 0.3)"
| '''''for Mayor'''''
|-<--Do not add a generic image here, that would be forbidden under WP:IPH-->
|[[File:Oh Se-Hoon.jpg|center|200x200px]]
|-
| style=width:16em|8th-9th<br>[[Mayor of Seoul]]<br>(2006-2011)
|-
|-
| '''Supported by'''
|-
|[[Ahn Cheol-soo]] ([[People Party (South Korea)|People]])<br>Keum Tae-seop ([[Independent politician|Independent]])
|-
|[http://xn--3e0b39yjva871a9mtleb.kr/view_ohsehoon.html '''Campaign''']
|-
|[[File:Campaign logo of the Oh Se-hoon for Seoul Mayor (2021).png|center|200x100px]]
|} </li>
</ul></div>

Because of [[First-past-the-post voting|first past the post voting]], South Korean politicians often try 'candidate unification' by opinion polls not to split the voters of their side.<ref>{{Cite web|date=2012-11-06|title=Candidate unification|url=http://www.koreatimes.co.kr/www/opinion/2021/02/202_124095.html|url-status=live|access-date=2021-02-26|website=[[The Korea Times]]|language=en}}</ref> In 2021 Seoul mayoral by-election, [[People Power Party (South Korea)|People Power Party]], [[People Party (South Korea)|People's Party]] and [[Independent politician|Independent]] candidate Keum Tae-seop agreed to unify their candidacy. According to the procedure they agreed on, in the first phase, the independent Keum Tae-seop and the People's Party unites their candidacy, and the winner of the first stage unify with the People Power Party candidate in the second stage.<ref>{{Cite news|last=윤다빈|date=3 February 2021|title=윤곽 잡힌 서울시장 야권 단일화 방식…‘2단계 경선’ 사실상 추진|language=ko|work=[[Dong-a Ilbo]]|url=https://www.donga.com/news/Politics/article/all/20210203/105265985/1|url-status=live|access-date=26 February 2021}}</ref> Meanwhile, the ruling [[Democratic Party of Korea|Democratic Party]] proposed unification to [[Open Democratic Party]] and [[Transition Korea]]. The candidates of each party expressed their stance in favor of the candidate unification.<ref>{{Cite news|last=장윤희|date=24 February 2021|title=범여권 서울시장 후보 단일화 시동…야권에 '맞불'|language=ko|work=Yonhap News TV|url=https://www.yonhapnewstv.co.kr/news/MYH20210224021700641|url-status=live|access-date=26 February 2021}}</ref>

As opposition coalition had announced their unified candidate on March 23, 2021 Seoul mayoral by-election became a two-way race between the pan-liberal candidate [[Park Young-sun]] and the pan-opposition candidate [[Oh Se-hoon]].<ref>{{Cite news|date=23 March 2021|title=Seoul Mayor Match Set: PPP Oh Se-hoon vs. Ruling DP Park Young-sun|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160334|url-status=live|access-date=25 March 2021|quote=Pan-Opposition Seoul Mayor candidate Oh Se-hoon ... Pan-Liberal Seoul mayoral candidate Park Young-sun}}</ref>
==== Ruling coalition ====
[[Open Democratic Party]] candidate [[Kim Jinai|Kim Jin-ae]] announced her resignation from the [[National Assembly (South Korea)|National Assembly]] to run for [[Mayor of Seoul|Seoul Mayor]] on 2 March 2021, and demanded fair unification rule to the Democratic Party and their candidate Park Young-sun.<ref>{{Cite news|last=[[News1]]|date=2 March 2021|title=김진애, 의원직 사퇴…“여권 단일화 불가피, 공정한 단일화 원해”|language=ko|trans-title=Kim Jin-ae resigns as a member of the National Assembly... “Unification is inevitable, I want fair unification”|work=[[Dong-a Ilbo]]|url=https://www.donga.com/news/Politics/article/all/20210302/105672432/1|url-status=live|access-date=9 March 2021}}</ref> Candidate Kim insisted on debating three times for unification, but the [[Democratic Party of Korea|Democratic Party]] that worried about running out of time to promote their candidate balked at this idea.<ref>{{Cite news|last=김진아|date=3 March 2021|title=여권 단일화 '시간싸움'…"토론 3번은 해야" vs "시간 없다"|language=ko|trans-title=Unification 'time fight'... "We need the debate at least three times" vs. "There's no time"|work=[[Newsis]]|url=https://newsis.com/view/?id=NISX20210303_0001357574|url-status=live|access-date=9 March 2021|archive-url=https://web.archive.org/web/20210308230818/https://newsis.com/view/?id=NISX20210303_0001357574|archive-date=3 March 2021}}</ref>

On 8 March 2021, [[Democratic Party of Korea|Democratic]] candidate [[Park Young-sun]] won the 1st round of candidate unification primary against [[Transition Korea]] candidate [[Cho Jung-hun]]. Details of the poll results were not released to the public.<ref>{{Cite news|last=남수현|date=8 March 2021|title=박영선, 조정훈 꺾고 범여 1차 단일화…오세훈 “안철수와 이번주 만나 논의”|language=ko|trans-title=Park Young-sun defeats Jo Jung-hoon and the first unification of the ruling side... Oh Se-Hoon said “I will meet and discuss with Ahn Cheol-soo this week”|work=[[JoongAng Daily]]|url=https://news.joins.com/article/24006561|url-status=live|access-date=9 March 2021}}</ref>

On 17 March 2021, Park Young-sun defeated [[Open Democratic Party]] candidate Kim Jin-ae in 2nd round of unification primary.<ref name=":15">{{Cite news|date=17 March 2021|title=DP's Park Young-sun Beats Rival to Become Ruling Coalition's Mayoral Candidate|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160222|url-status=live|access-date=22 March 2021}}</ref>

==== Opposition coalition ====
On 4 February 2021, [[People Party (South Korea)|People Party]] [[Ahn Cheol-soo]] and [[Independent politician|Independent]] [[Keum Tae-seop]] began to discuss the details of their unification.<ref>{{cite news |last1=박진만 |title='6년 악연' 딛고 마주한 안철수·금태섭, 단일화 협상 '시작' |url=https://www.hankookilbo.com/News/Read/A2021020415230001052 |access-date=1 March 2021 |work=[[Hankook Ilbo]] |date=4 February 2021}}</ref> Both sides agreed to hold a TV debate on [[February 18]], but there were some conflict over the details.<ref>{{cite news |last1=김미나 |title=안철수·금태섭 단일화 재가동…1차 토론 18일 열기로 |url=http://www.hani.co.kr/arti/politics/assembly/983066.html |access-date=1 March 2021 |work=[[The Hankyoreh]] |date=15 February 2021}}</ref> In the debate, [[Ahn Cheol-soo|Ahn]] and [[Keum Tae-seop|Keum]] clashed over annual [[Pride parade|LGBTQ Pride parade]]. [[Keum Tae-seop]] asked [[Ahn Cheol-soo|Ahn]] if he would be willing to participate on [[Pride parade]] if elected as the [[mayor of Seoul]].<ref name=":6">{{cite news |last1=Jung |first1=Da-min |title=Seoul mayoral candidate's remarks on LGBTQ bring controversy |url=https://www.koreatimes.co.kr/www/nation/2021/02/113_304371.html |access-date=1 March 2021 |work=[[The Korea Times]] |date=21 February 2021}}</ref> [[Ahn Cheol-soo]] opposed annual [[Pride parade]] in the [[Gwanghwamun Plaza|Gwanghwamun area]], saying "If we hold the Queer Festival in the Gwanghwamun area, there will be people voluntarily coming to see the festival there, but there are also others who have to be in the area for other reasons or who visit with their children. Their rights to refuse such things should be respected as well."<ref>{{cite news |last1=Ko |first1=Jun-tae |title=What Seoul mayor candidates have to say on LGBTQ festival |url=http://www.koreaherald.com/view.php?ud=20210223000701 |access-date=1 March 2021 |work=[[The Korea Herald]] |date=23 February 2021}}</ref> [[Keum Tae-seop|Keum]] criticized [[Ahn Cheol-soo|Ahn]]'s remarks in a radio interview the following day, saying he was disappointed as they lacked consideration for the basic [[human rights]] of the [[LGBT|LGBTQ]] community.<ref name=":6" /> And the progressive [[Justice Party (South Korea)|Justice Party]]'s Sexual Minority Committee criticized [[Ahn Cheol-soo|Ahn]]'s view and demand an apology for [[LGBT|LGBTQ]] people, stating "It is an open repression and oppression against [[LGBT|LGBTQ]] people by who do not view [[LGBT|LGBTQ]] as fellow citizens"<ref>{{Cite news|last=정진형|date=19 February 2021|title=정의당 "안철수, 성소수자는 동료 서울시민 아니란 거냐"|language=ko|work=[[Newsis]]|url=https://newsis.com/view/?id=NISX20210219_0001344857&cid=10303|url-status=live}}</ref>

On 1 March 2021, Ahn Cheol-soo won the 1st round of candidate unification primary. Details of the poll results were withheld in accordance with the National Election Commission's guidelines.<ref>{{cite news |title=Ahn Cheol-soo wins 1st round of primary for Seoul mayor candidacy |url=https://en.yna.co.kr/view/AEN20210301003600315 |access-date=1 March 2021 |work=[[Yonhap News Agency]] |date=1 March 2021}}</ref> After that, [[Oh Se-hoon]] and [[Ahn Cheol-soo]] have met and discussed on the unification process. They said both sides agreed on the need to field a unified candidate and that it would be desirable to do so before the candidate registration period expires.<ref>{{Cite news|date=8 March 2021|title=Oh, Ahn Open Talks on Fielding Unified Opp. Candidate in Seoul Mayor Race|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160003|url-status=live|access-date=22 March 2021}}</ref> On 16 March 2021, [[Ahn Cheol-soo]] said that he will seek to merge the [[People Party (South Korea)|People Party]] with [[People Power Party (South Korea)|People Power Party]] regardless of whether he defeats [[Oh Se-hoon]] in a unification primary.<ref name=":11">{{Cite news|date=16 March 2021|title=Ahn Vows to Seek Merger with PPP after Seoul Mayoral By-Election|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160181|url-status=live|access-date=22 March 2021}}</ref> [[Ahn Cheol-soo|Ahn]] hoped his plan would help ease concerns that he would abandon the PPP after becoming the unified candidate and launch a third party with former [[Prosecutor General of South Korea|Prosecutor General]] [[Yoon Seok-youl]], who is one of the leading potential 2022 presidential candidate.<ref name=":11" /> But, on March 18, the People Power Party and People's Party announced that they failed to make an agreement of procedures and other details before the registration period ends on March 19.<ref>{{Cite news|date=18 March 2021|title=PPP, People's Party Fail to Field Single Opposition Candidate|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160236|url-status=live|access-date=22 March 2021}}</ref>

On March 19, [[Ahn Cheol-soo]] announced that he would accept the PPP's conditions. But, on the same day, Oh Se-hoon pointed out that it has not been clarified as to what degree Ahn is willing to accept, and raised an issue with remarks by the People's Party secretary general, who said the percentage of landline phone survey results will be negotiated and the survey will include questions on who is a better candidate in terms of competitiveness.<ref>{{Cite news|date=19 March 2021|title=Oh Claims Ahn Hasn't Accepted Full Terms on Unified Opposition Candidate|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160271|url-status=live|access-date=22 March 2021}}</ref> The PPP had demanded 10 percent of the poll should be conducted through landline telephones and Ahn was known to have demanded the poll should only ask “competitiveness” of the candidates, not “adequacy”.<ref name=":12">{{Cite news|date=19 March 2021|title=Oh, Ahn Offer Concessions on Polling Method Ahead of Seoul Mayoral By-elections|work=[[KBS World Radio]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160274|url-status=live|access-date=22 March 2021}}</ref> Eventually, [[Oh Se-hoon]] and [[Ahn Cheol-soo]] held a separate press conference at the same time on the same day. [[Oh Se-hoon]] announced that he will accept the Ahn's demand that all votes in the primary be cast via mobile phones and Ahn also announced that he will accept the PPP’s demands on landline telephones.<ref name=":12" /> Some view this strange concession as a strategy to woo more voters to their side.<ref name=":12" /><ref>{{Cite news|last=곽우신|date=19 March 2021|title=오세훈의 헛웃음, 안철수의 한숨... 이상한 '양보전쟁'|language=ko|trans-title=Oh Se-hoon's vain laughter, Ahn Cheol-soo's sigh... strange 'concession War'|work=[[OhMyNews]]|url=http://www.ohmynews.com/NWS_Web/View/at_pg.aspx?CNTN_CD=A0002728545|url-status=live|access-date=22 March 2021}}</ref>

On March 23, both campaigns jointly announced [[Oh Se-hoon]]'s victory from two mobile surveys of a total 3,200 Seoul residents that evaluated the candidates' adequacy and competitiveness.<ref name=":16">{{Cite news|date=23 March 2021|title=Oh Defeats Ahn in Surveys to Determine Unified Opposition Candidate|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160329|url-status=live|access-date=25 March 2021}}</ref> [[Ahn Cheol-soo]] said he accepts the outcome, before vowing to work hard to help the unified opposition bloc win the election.<ref>{{Cite news|date=23 March 2021|title=Ahn Concedes Defeat, Vows to Assist in Opposition's Election Victory|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160332|url-status=live|access-date=25 March 2021}}</ref> [[Park Young-sun]] called [[Oh Se-hoon]] an outdated mayor who failed, while referring to herself as a mayor for the future.<ref>{{Cite news|date=23 March 2021|title=Park Young-sun: Seoul Race between Mayor of Future, Mayor of Past Failure|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160339|url-status=live|access-date=25 March 2021|quote=Park Young-sun, the ruling party candidate for April's Seoul mayoral by-election, called opposition bloc candidate Oh Se-hoon an outdated mayor who failed, while referring to herself as a mayor for the future.}}</ref>

=== Primary and Nomination ===
==== Democratic Party ====
[[Democratic Party of Korea|Democrats]] are worried about by-elections as two metropolitan mayors of their party dead or resigned due to sexual allegations.<ref>{{Cite web|date=2020-09-29|title=[4월 ‘미니대선’] 與, 서울·부산시장 후보 내긴 내야 하는데…|url=http://www.sisajournal.com/news/articleView.html?idxno=205648|access-date=2021-02-25|website=시사저널|language=ko}}</ref> The fact of the incident can not be confirmed as the investigation become impossible by death of Mayor Park, but it was said that it would be very disadvantageous to the [[Democratic Party of Korea|Democratic Party]].<ref name="parties1">{{Cite news|last=Yi|first=Whan-woo|date=5 December 2020|title=Parties gearing up for Seoul, Busan by-elections|work=[[The Korea Times]]|url=https://www.koreatimes.co.kr/www/nation/2020/12/356_300322.html|url-status=live|access-date=15 February 2021}}</ref> Moreover, since [[Seoul]] and [[Busan]] are the first and second [[List of cities in South Korea by population|cities in South Korea by population]], one of the biggest concerns of the Democratic Party is that this by-election which will be unfavorable to them may affect the [[2022 South Korean presidential election|2022 presidential election]].<ref name=":10">{{Cite news|last1=김형규|first1=|last2=박순봉|date=3 October 2020|title='대선 전초전' 될 서울·부산시장 보궐선거··· 여야 후보군 살펴보니|language=Korean|work=[[Kyunghyang Shinmun]]|url=http://news.khan.co.kr/kh_news/khan_art_view.html?art_id=202010030913001|url-status=live|access-date=16 February 2021}}</ref>

On 1 March 2021, Former [[Ministry of SMEs and Startups|Minister of SMEs and Startups]] [[Park Young-sun]] won the primary and become the [[Democratic Party of Korea|Democratic Party]] nominee in 2021 Seoul mayoral by-election, defeating Assemblyman [[Woo Sang-ho (politician)|Woo Sang-ho]].<ref>{{Cite news|last=노지원|date=1 March 2021|title=민주당, 서울시장 후보로 박영선 전 장관 확정|language=ko|work=[[The Hankyoreh]]|url=http://www.hani.co.kr/arti/politics/assembly/984954.html|url-status=live}}</ref> 
{| class=wikitable 
|+ style="background-color:#f2f2f2;margin-bottom:-1px;border:1px solid #aaa;padding:.2em .4em" | 2021 Seoul mayoral Democratic primary<ref>{{Cite news|last=노지원|date=1 March 2021|title=권리당원도 박영선에 ‘몰표’…‘본선 경쟁력’이 승패 갈랐다|language=ko|work=[[The Hankyoreh]]|url=http://www.hani.co.kr/arti/politics/assembly/984979.html|url-status=live|access-date=1 March 2021}}</ref>
! colspan="2" rowspan="2" style="width: 130px" |Party
! rowspan="2" style="width: 17em" |Candidate
! colspan="2" style="width: 8.5em" |Party members
! scope="col" style="width: 3.5em" |Poll
! scope="col" style="width: 4em" |SUM
|-
! scope="col" style="width: 5em" |Votes
! scope="col" style="width: 3.5em" |%
! scope="col" style="width: 3.5em" |%
! scope="col" style="width: 3.5em" |%
|-
| style="background-color:{{Democratic Party of Korea/meta/color}}" |
| style="width: 130px" | '''{{Democratic Party of Korea/meta/shortname}}'''
| '''[[Park Young-sun]]'''
| style="text-align:right;" | '''50,211'''
| style="text-align:right;" | '''63.54'''
| style="text-align:right;" | '''72.48'''
| style="text-align:right;" | '''69.56'''
|- class="vcard"
| style="background-color:{{Democratic Party of Korea/meta/color}}" |
| class="org" style="width: 130px" | {{Democratic Party of Korea/meta/shortname}}
| class="fn" | [[Woo Sang-ho (politician)|Woo Sang-ho]]
| style="text-align:right;" | 28,814
| style="text-align:right;" | 36.46
| style="text-align:right;" | 28.52
| style="text-align:right;" | 30.44
|- style="background-color:#F6F6F6" 
! colspan="3" style="text-align: right; margin-right: 0.5em" | Turnout 
| style="text-align: right; margin-right: 0.5em" | 79,025 
| style="text-align: right; margin-right: 0.5em" | 53.52
! colspan="2" style="text-align: right; margin-right: 0.5em" |
|-
|- style="background-color:#F6F6F6" 
! colspan="3" style="text-align: right; margin-right: 0.5em" | Registered electors 
| style="text-align: right; margin-right: 0.5em" | 147,642
| style="text-align: right; margin-right: 0.5em" | 100
! colspan="2" style="text-align: right; margin-right: 0.5em" |
|-
|}

* '''[[Park Young-sun]], Former [[Ministry of SMEs and Startups|Minister of SMEs and Startups]] (2019-2021) - (Nominated)'''<ref>{{cite news|last1=Shin|first1=Ji-hye|date=26 January 2021|title=Former SMEs minister runs for Seoul mayor|work=[[The Korea Herald]]|url=http://www.koreaherald.com/view.php?ud=20210126000808&ACE_SEARCH=1|access-date=16 February 2021}}</ref>
*[[Woo Sang-ho (politician)|Woo Sang-ho]], Former Floor Leader of the [[Democratic Party of Korea|Democratic Party]] in the [[National Assembly (South Korea)|National Assembly]]<ref>{{cite news |last1=노지원 |title=우상호, 서울시장 출마선언 "마지막 정치적 도전" |url=http://www.hani.co.kr/arti/politics/assembly/973939.html |access-date=16 February 2021 |work=[[The Hankyoreh]] |date=13 December 2020|language=Korean}}</ref>
<gallery mode="packed" heights="160">
File:At Namdaemun Market in Jung-gu, Seoul on the morning of 23rd Woo Sang-ho are Taking commemorative photos (3) (cropped).jpg|{{center|Former floor leader of the [[Democratic Party of Korea|Democratic Party]]<br/>'''[[Woo Sang-ho (politician)|Woo Sang-ho]]'''}}
File:At Namdaemun Market in Jung-gu, Seoul on the morning of 23rd candidates for the Seoul mayor Park Young-sun (Interview) (cropped).jpg|{{center|Former [[Ministry of SMEs and Startups|Minister of SMEs and Startups]]<br/>'''[[Park Young-sun]]'''}} 
</gallery>

==== People Power Party ====
On 4 March 2021, [[People Power Party (South Korea)|People Power Party]] announced the result and the winner of the primary. Former [[Mayor of Seoul|Seoul Mayor]] [[Oh Se-hoon]] was selected as the [[People Power Party (South Korea)|People Power Party]]'s candidate to run 2021 Seoul mayoral by-election.<ref>{{cite news |title=PPP Elects Oh Se-hoon, Park Heong-joon as Candidates for Mayoral Posts |url=http://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=159923 |access-date=4 March 2021 |work=[[KBS World]] |date=4 March 2021}}</ref> [[Oh Se-hoon]] won 41.64 percent of the support and his primary rival [[Na Kyung-won]] won 36.31 percent.<ref>{{cite news|title=[Newsmaker] Ex-Seoul Mayor Oh Se-hoon wins main opposition's ticket for Seoul mayoral election|work=[[The Korea Herald]]|agency=[[Yonhap News Agency]]|url=http://www.koreaherald.com/view.php?ud=20210304000239&ACE_SEARCH=1|access-date=4 March 2021}}</ref>
{| class=wikitable 
|+ style="background-color:#f2f2f2;margin-bottom:-1px;border:1px solid #aaa;padding:.2em .4em" | 2021 Seoul mayoral People Power Party primary<ref>{{Cite web|last=나확진|date=2021-03-04|title=국민의힘 서울시장 후보에 오세훈…부산은 박형준(종합)|url=https://www.yna.co.kr/view/AKR20210304070900001|access-date=2021-03-04|website=연합뉴스|language=ko}}</ref>
! colspan="2" style="width: 130px" |Party
! style="width: 17em" |Candidate
!Poll (%)
|-
| style="background-color:{{People Power Party (South Korea)/meta/color}}" |
| style="width: 130px" | '''{{People Power Party (South Korea)/meta/shortname}}'''
| '''[[Oh Se-hoon]]'''
| style="text-align:right;" | '''41.64'''
|- class="vcard"
| style="background-color:{{People Power Party (South Korea)/meta/color}}" |
| class="org" style="width: 130px" | {{People Power Party (South Korea)/meta/shortname}}
| class="fn" | [[Na Kyung-won]]
| style="text-align:right;" | 36.31
|- class="vcard"
| style="background-color:{{People Power Party (South Korea)/meta/color}}" |
| class="org" style="width: 130px" | {{People Power Party (South Korea)/meta/shortname}}
| class="fn" | [[Cho Eun-hee (politician)|Cho Eun-hee]]
| style="text-align:right;" | 16.47
|- class="vcard"
| style="background-color:{{People Power Party (South Korea)/meta/color}}" |
| class="org" style="width: 130px" | {{People Power Party (South Korea)/meta/shortname}}
| class="fn" | [[Oh Shin-hwan]]
| style="text-align:right;" | 10.39
|-
|-
|}

*'''[[Oh Se-hoon]], Former [[Mayor of Seoul]] (2006-2011) - (Nominated)<ref>{{cite news|last1=Shin|first1=Ji-hye|date=27 January 2021|title=Former Seoul Mayor Oh Se-hoon to run in by-election|work=[[The Korea Herald]]|url=http://www.koreaherald.com/view.php?ud=20210117000153|access-date=17 February 2021}}</ref>'''
*[[Oh Shin-hwan]], Former Member of the [[National Assembly (South Korea)|National Assembly]] (2015-2020)<ref name="debate of Oh and Cho">{{cite news |title=PPP Primary Candidates to Hold First 1:1 Debates |url=https://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=159585 |access-date=17 February 2021 |work=[[KBS World]] |date=16 February 2021}}</ref>
*[[Na Kyung-won]], Former Floor Leader of the [[Liberty Korea Party]] in the [[National Assembly (South Korea)|National Assembly]]<ref>{{cite news |title=Former PPP Floor Leader Na Kyung-won Unveils Bid for Seoul Mayor |url=https://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=158875 |access-date=17 February 2021 |work=[[KBS World]] |date=13 January 2021}}</ref>
*[[Cho Eun-hee]], Mayor of [[Seocho District]] (2018-present)<ref name="debate of Oh and Cho">{{cite news |title=PPP Primary Candidates to Hold First 1:1 Debates |url=https://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=159585 |access-date=17 February 2021 |work=[[KBS World]] |date=16 February 2021}}</ref>
*''[[Lee Hye-hoon]], Former Member of the [[National Assembly (South Korea)|National Assembly]] (withdrawn)''<ref>{{Cite news|last=김혜린|date=19 November 2020|title=이혜훈, 서울시장 출마 선언 "경제시장 되겠다"|language=Korean|work=Seoul Economy|url=https://www.sedaily.com/NewsVIew/1ZAGVUT7O8|url-status=live|access-date=18 February 2021}}</ref><ref>{{Cite news|last=주희연|date=9 January 2021|title=이혜훈 "경선 갈등 막겠다" 서울시장 불출마 선언|language=Korean|work=[[The Chosun Ilbo]]|url=https://www.chosun.com/politics/2021/01/19/W5CKZUNXTRD3XEQQJRPO7IN4TI/|url-status=live|access-date=18 February 2021}}</ref>
*''[[Kim Geun-sik]] (eliminated)''<ref name=":1">{{Cite news|last=한지훈|date=5 February 2021|title=국민의힘, 서울·부산시장 본경선 진출자 확정(종합2보)|language=Korean|work=[[Yonhap News Agency]]|url=https://www.yna.co.kr/view/AKR20210205060353001|url-status=live|access-date=18 February 2021}}</ref>
*''[[Kim Seon-dong (politician, born 1963)|Kim Seon-dong]], Former Secretary-General of the [[People Power Party (South Korea)|People Power Party]] (eliminated)<ref name=":1" />'' 
*''[[Lee Seong-hyeon (politician)|Lee Seong-hyeon]] (eliminated)<ref name=":1" />'' 
*''[[Lee Jong-gu]] (eliminated)<ref name=":1" />'' 

<gallery mode="packed" heights="160">
File:Oh Shin-wan, Member of the National Assembly, in press conference.png|{{center|Former member of the National Assembly<br/>'''[[Oh Shin-hwan]]'''}}
File:Oh Se-Hoon.jpg|{{center|Former [[Mayor of Seoul]]<br/>'''[[Oh Se-hoon]]'''}}
File:Na Kyung-won against damaging the remaining greenbelt that is decades old (5) (cropped).jpg|{{center|Former floor leader of the [[Liberty Korea Party]]<br/>'''[[Na Kyung-won]]'''}}
File:Seal of Seoul, South Korea.svg|{{center|Mayor of Seocho district<br/>'''[[Cho Eun-hee]]'''}}  
</gallery>


==== Justice Party ====
On {{dts|2021|2|3}}, Justice Party decided not to field candidates in the April mayoral by-elections after its leader was expelled for a sexual abuse scandal.<ref>{{cite news |title=Justice Party Decides Not to Field Candidates in Mayoral By-elections |url=https://world.kbs.co.kr/service/news_view.htm?lang=e&Seq_Code=159359 |access-date=17 February 2021 |work=[[KBS World]] |date=4 February 2021}}</ref>
====People's Party====
* [[Ahn Cheol-soo]], Chairman of the [[People Party (South Korea)|People's Party]]<ref>{{cite news |last1=Choi |first1=He-suk |title=Ahn Cheol-soo to run for Seoul mayor |url=http://www.koreaherald.com/view.php?ud=20201220000122 |access-date=17 February 2021 |work=[[The Korea Herald]] |date=20 December 2020}}</ref>
<gallery mode="packed" heights="160">
File:Ahn Cheol-Soo cropped (cropped).jpg|{{center|Chairman of the [[People Party (South Korea)|People's Party]]<br/>'''[[Ahn Cheol-soo]]'''}}
</gallery>

====Open Democratic Party====
[[Kim Jinai|Kim Jin-ae]] was nominated as the candidate of [[Open Democratic Party]] on 9 February 2021. The Open Democratic Party announced on same day that [[Kim Jinai|Kim Jin-ae]] received 3660 votes (66.3%) out of the total number of votes 5518 in the primary, overtaking former lawmaker [[Chung Bong-ju]]. [[Chung Bong-ju]] won 1858 votes (33.7%).<ref name=":0">{{cite news |last1=김원철 |title=김진애, 정봉주 꺾고 열린민주당 서울시장 후보 확정 |url=http://www.hani.co.kr/arti/politics/assembly/982453.html |access-date=17 February 2021 |work=[[The Hankyoreh]] |date=9 February 2021|language=Korean}}</ref>
* '''[[Kim Jinai|Kim Jin-ae]], Member of the National Assembly - (nominated)<ref name=":0" />'''<ref>{{cite news |last1=김지현 |title="첫 도시전문가 시장 될것" 김진애, 출마 선언…김의겸 국회 입성? |url=https://www.donga.com/news/Politics/article/all/20201227/104653556/1 |access-date=17 February 2021 |work=[[The Dong-a Ilbo]] |date=27 December 2020|language=Korean}}</ref>
* [[Chung Bong-ju]], Former Member of the National Assembly<ref>{{cite news |last1=Heo |first1=Dong-jun |title=Woo Sang-ho, Chung Bong-ju agree to unify Seoul mayor candidacy |url=https://www.donga.com/en/article/all/20210208/2424280/1/Woo-Sang-ho-Chung-Bong-ju-agree-to-unify-Seoul-mayor-candidacy |access-date=17 February 2021 |work=[[The Dong-a Ilbo]] |date=8 February 2021}}</ref>
<gallery mode="packed" heights="160">
File:Kim Jin-ai in Lee & Hong (cropped) (1).jpg|{{center|Member of the [[National Assembly (South Korea)|National Assembly]]<br/>'''[[Kim Jinai|Kim Jin-ae]]'''}}
File:JBJ.JPG|{{center|Former member of the [[National Assembly (South Korea)|National Assembly]]<br/>'''[[Chung Bong-ju]]'''}}
</gallery>

==== Other parties ====
* [[Basic Income Party]]: [[Shin Ji-hye]], Leader of the [[Basic Income Party]],<ref>{{Cite news|last=이혜인|date=8 December 2020|title=기본소득당 신지혜 서울시장 출마···"1인당 50만원 기본소득"|language=Korean|trans-title=Shin Ji-hye (Basic Income Party) runs for Mayor of Seoul... "Basic income of 500,000 won per person"|work=[[:ko:서울경제{{!}}]]|url=https://www.sedaily.com/NewsView/1ZBLRZWV94|url-status=live|access-date=18 February 2021}}</ref> not to be confused with [[Green Party Korea]]'s Shin Jiye, [[2018 Seoul mayoral election]] candidate.
* [[Transition Korea]]: [[Cho Jung-hun]], President of the [[Transition Korea]]<ref name=":2">{{Cite news|last=조준혁|date=31 January 2021|title=금태섭·조정훈, 서울시장 출마선언…군소후보들 잰걸음|language=Korean|trans-title=Keum Tae-seop and Cho Jung-hun declared running for mayor of Seoul... Small party candidates and independents started to run|work=[[Korea Economic Daily]]|url=https://www.hankyung.com/politics/article/2021013104497|url-status=live|access-date=18 February 2021}}</ref>
*[[Minsaeng Party|Misaeng Party]]: [[Chung Dong-hui]], Writer<ref name=":7" />
* [[Progressive Party (South Korea, 2017)|Progressive Party]]: Song Myeong-suk, Co-Leader of the [[Progressive Party (South Korea, 2017)|Progressive Party]]<ref>{{Cite news|last=진성철|date=22 January 2021|title=서울시장 출마선언하는 진보당 송명숙 공동대표|language=Korean|trans-title=Song Myeong-sook, Co-Leader of the Progressive Party, declaring to run for mayor of Seoul|work=[[Yonhap News Agency]]|url=https://www.yna.co.kr/view/PYH20210122067300013|url-status=live|access-date=18 February 2021}}</ref>
* [[National Revolutionary Dividends Party]]: [[Huh Kyung-young]], President of the [[National Revolutionary Dividends Party]]<ref>{{Cite news|last=박지혜|date=23 December 2020|title=허경영 "서울시장 출마한다"|language=Korean|work=[[News1]]|url=https://www.news1.kr/photos/view/?4541106|url-status=live|access-date=18 February 2021}}</ref>
* [[Our Future]]: [[Oh Tae-yang]], President of the [[Our Future]]<ref>{{Cite web|title=[보도자료] 청년정당 미래당 오태양 서울시장 출마 등, 4월 보궐선거 출마선언 "정권교체선거 안돼"|trans-title=[Press Release] Our Future Party, Oh Taeyang runs for Mayor of Seoul, Declaration to run for by-election in April "This election should not be a regime change election"|url=https://makeourfuture.kr/%EC%A0%84%EC%B2%B4/news/%EB%B3%B4%EB%8F%84%EC%9E%90%EB%A3%8C-%EC%B2%AD%EB%85%84%EC%A0%95%EB%8B%B9-%EB%AF%B8%EB%9E%98%EB%8B%B9-%EC%98%A4%ED%83%9C%EC%96%91-%EC%84%9C%EC%9A%B8%EC%8B%9C%EC%9E%A5-%EC%B6%9C%EB%A7%88-%EB%93%B1-4/|url-status=live|access-date=18 February 2021|website=[[Our Future]]|language=korean}}</ref>
* [[Women's Party (South Korea)|Women's Party]]: [[Kim Jin-ah]], Co-Leader of the [[Women's Party (South Korea)|Women's Party]]<ref name=":7">{{Cite web|last=진혜민|date=19 February 2021|title=[4·7 보궐선거] “우리를 주목하라” 소수정당 서울시장 예비후보자들|url=http://www.womennews.co.kr/news/articleView.html?idxno=207713|url-status=live|access-date=2021-03-01|website=여성신문|language=ko}}</ref>

==== Independents ====
* [[Kim Dae-ho (politician)|Kim Dae-ho]], Director of Social Design Research Institute<ref>{{Cite news|last=이재희|date=29 December 2020|title=서울시장 출마 선언하는 김대호|language=Korean|work=[[Yonhap News Agency]]|url=https://www.yna.co.kr/view/PYH20201229087900013|url-status=live|access-date=18 February 2021}}</ref>
*[[Keum Tae-seop]], Former Member of the [[National Assembly (South Korea)|National Assembly]]<ref name=":2" />
*Shin Ji-ye, 2018 [[Green Party Korea]] candidate for [[Mayor of Seoul|Seoul Mayor]]<ref>{{Cite news|last=이철영|date=5 March 2021|title=신지예, 서울시장 출마 선언…"여야, 흑역사 만든 주범들"|trans-title=Shin Ji-ye declares running for mayor of Seoul... "Established politicians, the main criminals who made the dark days|work=The Fact|url=https://n.news.naver.com/article/629/0000070739|url-status=live|access-date=9 March 2021|archive-url=https://web.archive.org/web/20210308233608/https://n.news.naver.com/article/629/0000070739|archive-date=9 March 2021}}</ref>

=== Debates ===
====Major candidates ====
{| class="wikitable" style="font-size:85%"
|-
! style="white-space:nowrap;" | No. || Date and time || Host || Programme || Broadcaster || Presenter(s) || Viewer<br>rating
! colspan="3" scope="col" | Candidates
! rowspan="2" |Link
|-
! colspan="7" |<small>{{Colors|black|#99ff99|&nbsp;P&nbsp;}} Participant &nbsp;  {{Colors|black|#ff9999|&nbsp;A&nbsp;}} Absent invitee &nbsp;   {{Colors|black|#ececec| &nbsp;O&nbsp; }}  Out of race (eliminated or withdrawn) &nbsp;  {{Colors|black|#ffffdd| &nbsp;N&nbsp;}} Non-invitee</small>
! scope="col" style="width:7em;" |[[Park Young-sun|Park<br>Young-sun]]
! scope="col" style="width:7em;" |[[Oh Se-hoon|Oh<br>Se-hoon]]
! scope="col" style="width:7em;" |Lee<br>Su-bong
|- style="height: 3.5em;"
! 1
| style="white-space:nowrap;" |29 March 2021; 22:40-24:20 [[Korea standard time|KST]]
| style="white-space:nowrap;" |[[Munhwa Broadcasting Corporation|MBC]]
| style="white-space:nowrap;" |''[[Munhwa Broadcasting Corporation|MBC]] 100min Debate''
| style="white-space:nowrap;" |[[Munhwa Broadcasting Corporation|MBC]]
| style="white-space:nowrap;" |Chung Jun-hee
|6.2%<ref name=":13">{{Cite news|last=이정현|date=31 March 2021|title=박영선-오세훈 2차 TV토론 시청률 8.7％…1차보다 높아|language=ko|work=[[Yonhap News Agency]]|url=https://www.yna.co.kr/view/AKR20210331042000005|url-status=live}}</ref>
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{okay|'''N'''}}
|[https://www.youtube.com/watch?v=slf9pZLDd-s Youtube]
|- style="height: 3.5em;"
! 2
| style="white-space:nowrap;" |30 March 2021; 22:00-24:00 [[Korea standard time|KST]]
| style="white-space:nowrap;" |[[National Election Commission (South Korea)|National Election Commission]]
| style="white-space:nowrap;" |''2021 Seoul Mayoral by-election''<br>''invited candidate debate''
| style="white-space:nowrap;" |[[KBS1]]/[[Munhwa Broadcasting Corporation|MBC]]
| style="white-space:nowrap;" |Park Tae-seo
| 8.7%<ref name=":13" />
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|[https://www.debates.go.kr/2021_vote/vote_view.php?year=2021&debate=&search_key=&search_word=&ctg=&sub_ctg=1&type=&sido=&gu=&id=613&offset=0 Website]
|- style="height: 3.5em;"
! 3
| style="white-space:nowrap;" |5 April 2021; 14:00-15:30 [[Korea standard time|KST]]
| style="white-space:nowrap;" |Korean Broadcasting Journalists Club
| style="white-space:nowrap;" |''Korean Broadcasting Journalists Club''<br>''invitational Debate''
| style="white-space:nowrap;" |[[KBS1]], [[Munhwa Broadcasting Corporation|MBC]], [[Seoul Broadcasting System|SBS]],<br>[[YTN]],[[Maeil Broadcasting Network|MBN]], [[Christian Broadcasting System|CBS]]
| style="white-space:nowrap;" |Chung Kwan-yong
| 2.1%<ref>{{Cite news|date=6 April 2021|title=박영선-오세훈 마지막 TV 토론 시청률 2.1％|work=한국경제|url=https://www.hankyung.com/politics/article/202104061808Y|url-status=live}}</ref>
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{okay|'''N'''}}
|[https://www.youtube.com/watch?v=FGBWA8WUxB4 Youtube]
|}
During the first televised debate, both candidate clashed with real estate issues and Moon Jae-in administration's anti-speculative policies amid LH scandal. Park Young-sun raised allegations against Oh Se-hoon that he received 3.65 billion [[Korean won|KRW]] in 2009 in compensation for land in Seoul's Seocho district, after his involvement in the area being designated a residential zone. Oh Se-hoon denied that he was aware of the land under his wife's name or the development plan. Oh Se-hoon then attacked Moon administration's housing policies aimed at curbing soaring housing prices, saying the government policies have only served to exacerbate the problem and start a vicious economic cycle. Park Young-sun acknowledged some failure in the polices and said she will introduce new measures.<ref>{{Cite news|date=30 March 2021|title=Rival Candidates Clash over Real Estate Issues during Live Debate|work=[[KBS World]]|url=http://world.kbs.co.kr/service/news_view.htm?lang=e&id=Po&Seq_Code=160487|url-status=live|access-date=7 April 2021}}</ref>

==== Minor candidates ====
{| class="wikitable" style="font-size:85%"
|-
! style="white-space:nowrap;" | No. || Date and time || Host || Programme || Broadcaster || Presenter(s) 
! colspan="9" scope="col" | Candidates
! rowspan="2" |Link
|-
! colspan="6" |<small>{{Colors|black|#99ff99|&nbsp;P&nbsp;}} Participant &nbsp;  {{Colors|black|#ff9999|&nbsp;A&nbsp;}} Absent invitee &nbsp;   {{Colors|black|#ececec| &nbsp;O&nbsp; }}  Out of race (eliminated or withdrawn) &nbsp;  {{Colors|black|#ffffdd| &nbsp;N&nbsp;}} Non-invitee</small>
! scope="col" style="width:7em; font-size:85%;" |Shin<br/>Ji-hye
! scope="col" style="width:7em; font-size:85%;" |Huh<br/>Kyoung-young
! scope="col" style="width:7em; font-size:85%;" |Oh<br>Tae-yang
! scope="col" style="width:7em; font-size:85%;" |Bae<br/>Yeong-hyu
! scope="col" style="width:7em; font-size:85%;" |Kim<br/>Jin-ah
! scope="col" style="width:7em; font-size:85%;" |Song<br/>Myeong-suk
! scope="col" style="width:7em; font-size:85%;" |Chung<br/>Dong-hui
! scope="col" style="width:7em; font-size:85%;" |Lee<br/>Do-yeop
! scope="col" style="width:7em; font-size:85%;" |Shin<br/>Ji-ye
|- style="height: 3.5em;"
! 1
| style="white-space:nowrap;" |29 March 2021; 14:30-16:30 [[Korea standard time|KST]]
| style="white-space:nowrap;" |[[National Election Commission (South Korea)|National Election Commission]]
| style="white-space:nowrap;" |''2021 Seoul Mayoral by-election''<br>''non-invited candidate debate''
| style="white-space:nowrap;" |[[KBS1]]/[[Munhwa Broadcasting Corporation|MBC]]
| style="white-space:nowrap;" |Lee Kyu-won
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|{{Yes|'''P'''}}
|[https://www.debates.go.kr/2021_vote/vote_view.php?year=2021&debate=&search_key=&search_word=&ctg=&sub_ctg=1&type=&sido=&gu=&id=617&offset=0 Website]
|}

=== Polling ===
{| class="wikitable" style="font-size:90%;"
|- valign="bottom"
! Poll source
! Client
! Date(s)<br>administered
! Method
! Sample<br>size
! Margin<br>of Error
! style="width:75px;" | Park<br>Young-sun
! style="width:75px;" | Woo<br>Sang-ho
! style="width:75px;" | Ahn<br>Cheol-soo
! style="width:75px;" | Oh<br>Se-hoon
! style="width:78px;" | Na<br>Kyoung-won
! style="width:75px;" | Cho<br>Eun-hee
! style="width:75px;" | Keum<br>Tae-seop
! style="width:75px;" | Kim<br>Jin-ai
! Others
! None
! Don't know<br>or no answer
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103150243145070.pdf.htm Next Research]
| [[Seoul Broadcasting System|SBS]]
| align="center" | March 13, 2021 
| align="center" | LI(M-VN)
| align="center" | 1,008
| align="center" | 95%, ±3.1%p
| {{party shading/Democratic Party of Korea}} align="center" | '''27.4%'''
| align="center" | –
| align="center" | 24.0%
| align="center" | 26.1%
| align="center" | –
| align="center" | –
| align="center" | –
| align="center" | 2.4%
| {{party shading/Undecided}} align="center" |'''1.0%'''
| {{party shading/Undecided}} align="center" |'''17.4%'''
| {{party shading/Undecided}} align="center" |'''1.8%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103100307091200.pdf.htm Hankook Research]
| [[Korean Broadcasting System|KBS]]
| align="center" | March 8-9, 2021 
| align="center" | LI(M-VN)
| align="center" | 800
| align="center" | 95%, ±3.5%p
| {{party shading/Democratic Party of Korea}} align="center" | '''30.5%'''
| align="center" | –
| align="center" | 22.4%
| align="center" | 23.1%
| align="center" | –
| align="center" | –
| align="center" | –
| align="center" | 2.1%
| {{party shading/Undecided}} align="center" |'''1.6%'''
| {{party shading/Undecided}} align="center" |'''11.1%'''
| {{party shading/Undecided}} align="center" |'''9.1%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103080459593791.pdf.htm Embrain Public]
| [[News1]]
| align="center" | March 7-8, 2021 
| align="center" | LI(M-VN)
| align="center" | 1,009
| align="center" | 95%, ±3.1%p
| {{party shading/Democratic Party of Korea}} align="center" | '''33.3%'''
| align="center" | –
| align="center" | 23.4%
| align="center" | 24.6%
| align="center" | –
| align="center" | –
| align="center" | –
| align="center" | 2.9%
| {{party shading/Undecided}} align="center" |'''1.5%'''
| {{party shading/Undecided}} align="center" |'''11.2%'''
| {{party shading/Undecided}} align="center" |'''3.1%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103081131073670.pdf.htm WinG Korea]
| Asia Economy
| align="center" | March 6-7, 2021 
| align="center" | ARS(M-VN)
| align="center" | 1,002
| align="center" | 95%, ±3.1%p
| {{party shading/Democratic Party of Korea}} align="center" | '''30.3%'''
| align="center" | –
| align="center" | 24.7%
| align="center" | 27.9%
| align="center" | –
| align="center" | –
| align="center" | –
| align="center" | 4.1%
| {{party shading/Undecided}} align="center" |'''2.3%'''
| {{party shading/Undecided}} align="center" |'''8.0%'''
| {{party shading/Undecided}} align="center" |'''2.0%'''
|-
| [https://www.nesdc.go.kr/files/result/202103/FILE_202102220508222030.pdf.htm Realmeter]
| [[Munhwa Broadcasting Corporation|MBC]] 100min Debate
| align="center" | February 19-20, 2021 
| align="center" | {{small|ARS<br>(M-VN 80%, L-RDD 20%)}}
| align="center" | 1,030
| align="center" | 95%, ±3.1%p
| {{party shading/Democratic Party of Korea}} align="center" | '''31.1%'''
| align="center" | 7.3%
| align="center" | 23.2%
| align="center" | 9.4%
| align="center" | 14.2%
| align="center" | 1.9%
| align="center" | 1.9%
| align="center" | 2.5%
| {{party shading/Undecided}} align="center" |'''1.5%'''
| {{party shading/Undecided}} align="center" |'''5.3%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| [https://www.nesdc.go.kr/files/result/202102/FILE_202102090321062280.pdf.htm Realmeter]
| [[Traffic Broadcasting System|TBS]], [[YTN]]
| align="center" | February 7-8, 2021 
| align="center" | {{small|LI 50%, ARS 50%<br>(M-RDD 80%, L-RDD 20%)}}
| align="center" | 1,016
| align="center" | 95%, ±3.1%p
| {{party shading/Democratic Party of Korea}} align="center" | '''26.2%'''
| align="center" | 7.7%
| align="center" | 19.0%
| align="center" | 9.4%
| align="center" | 15.1%
| align="center" | 2.8%
| align="center" | 1.4%
| align="center" | 1.3%
| {{party shading/Undecided}} align="center" |'''2.8%'''
| {{party shading/Undecided}} align="center" |'''11.5%'''
| {{party shading/Undecided}} align="center" |'''2.7%'''
|-
! colspan="17" |For more information, visit the [https://www.nesdc.go.kr/portal/main.do National Election Survey Deliberation Committee]<!-- Recommend to include "visit the National Election Survey Deliberation Committee". When publishing an election-related opinion poll in South Korea, name of the poll requester, name of the polling agency, the date of the poll, and the phrase "visit the website of the National Election Poll Deliberation Committee" must all be included. The absence of any of these may violate the Korean Public Official Election Act. There are no such regulations in US law, but I recommended to include this phrase. -->
|}
{{Hidden begin |title=Virtual polling (two-way)}}
{| class="wikitable" style="font-size:90%;"
|- valign=bottom
! Poll source
! Client
! Date(s)<br>administered
! Method
! Sample<br>size
! Margin<br>of Error
! style="width:75px;" | Woo<br>Sang-ho
! style="width:75px;" | Park<br>Young-sun
! style="width:75px;" | Ahn<br>Cheol-soo
! style="width:75px;" | Oh<br>Se-hoon
! style="width:78px;" | Na<br>Kyoung-won
!Others
! None
! Don't know<br>or no answer
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103150214379490.pdf.htm PNR]
| rowspan="2" | Mirae Hankook Research<br>[[Aju Business Daily]]
| rowspan="2" align="center" | March 14, 2021 
| rowspan="2" align="center" | {{small|ARS<br>(M-VN 84% L-RDD 16%)}}
| rowspan="2" align="center" | 806
| rowspan="2" align="center" | 95%, ±3.5%p
| align="center" | –
| align="center" | 34.1%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''47.7%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''8.1%'''
| {{party shading/Undecided}} align="center" |'''6.6%'''
| {{party shading/Undecided}} align="center" |'''3.5%'''
|-
| align="center" | –
| align="center" | 33.0%
| {{party shading/People Party (South Korea)}} align="center" | '''50.8%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''8.4%'''
| {{party shading/Undecided}} align="center" |'''5.4%'''
| {{party shading/Undecided}} align="center" |'''2.5%'''
|-
| rowspan="2" |[https://www.nesdc.go.kr/files/result/202104/FILE_202103150433334300.pdf.htm Kanta Korea]
| rowspan="2" |[[The Chosun Ilbo]]/[[TV Chosun]]
| align="center" rowspan="2" |March 13, 2021
| align="center" rowspan="2" |ARS(M-VN)
| align="center" rowspan="2" |806
| align="center" rowspan="2" |95%, ±3.5%p
| align="center" | –
| align="center" | 34.2%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''46.5%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.6%'''
| {{party shading/Undecided}} align="center" |'''3.8%'''
| {{party shading/Undecided}} align="center" |'''14.9%'''
|-
| align="center" | –
| align="center" | 33.8%
| {{party shading/People Party (South Korea)}} align="center" | '''45.2%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.9%'''
| {{party shading/Undecided}} align="center" |'''3.2%'''
| {{party shading/Undecided}} align="center" |'''15.9%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103150433334300.pdf.htm STI]
| rowspan="2" | STI
| rowspan="2" align="center" | March 12-13, 2021 
| rowspan="2" align="center" | ARS(M-VN)
| rowspan="2" align="center" | 1,000
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| align="center" | 33.1%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''51.8%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''8.0%'''
| {{party shading/Undecided}} align="center" |'''4.9%'''
| {{party shading/Undecided}} align="center" |'''2.4%'''
|-
| align="center" | –
| align="center" | 32.3%
| {{party shading/People Party (South Korea)}} align="center" | '''53.7%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''5.7%'''
| {{party shading/Undecided}} align="center" |'''5.8%'''
| {{party shading/Undecided}} align="center" |'''2.4%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103150243145070.pdf.htm Next Research]
| rowspan="2" | [[Seoul Broadcasting System|SBS]]
| rowspan="2" align="center" | March 13, 2021 
| rowspan="2" align="center" | LI(M-VN)
| rowspan="2" align="center" | 1,008
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| align="center" | 35.0%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''42.3%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''3.9%'''
| {{party shading/Undecided}} align="center" |'''17.2%'''
| {{party shading/Undecided}} align="center" |'''1.5%'''
|-
| align="center" | –
| align="center" | 33.6%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''45.4%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.2%'''
| {{party shading/Undecided}} align="center" |'''17.7%'''
| {{party shading/Undecided}} align="center" |'''1.1%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103140419233060.pdf.htm PNR]
| rowspan="2" | Mirae Hankook Research/<br>Money Today
| rowspan="2" align="center" | March 13, 2021 
| rowspan="2" align="center" | {{small|ARS<br>(M-VN 81% L-RDD 19%)}}
| rowspan="2" align="center" | 802
| rowspan="2" align="center" | 95%, ±3.5%p
| align="center" | –
| align="center" | 36.1%
| {{party shading/People Party (South Korea)}} align="center" | '''46.2%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''9.1%'''
| {{party shading/Undecided}} align="center" |'''5.7%'''
| {{party shading/Undecided}} align="center" |'''3.0%'''
|-
| align="center" | –
| align="center" | 34.8%
| {{party shading/People Party (South Korea)}} align="center" | '''46.7%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''9.8%'''
| {{party shading/Undecided}} align="center" |'''5.2%'''
| {{party shading/Undecided}} align="center" |'''3.5%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103100307091200.pdf.htm Hankook Research]
| rowspan="2" | [[Korean Broadcasting System|KBS]]
| rowspan="2" align="center" | March 8-9, 2021 
| rowspan="2" align="center" | LI(M-VN)
| rowspan="2" align="center" | 800
| rowspan="2" align="center" | 95%, ±3.5%p
| align="center" | –
| align="center" | 39.5%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''44.3%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.3%'''
| {{party shading/Undecided}} align="center" |'''9.1%'''
| {{party shading/Undecided}} align="center" |'''4.9%'''
|-
| align="center" | –
| align="center" | 37.0%
| {{party shading/People Party (South Korea)}} align="center" | '''44.9%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.8%'''
| {{party shading/Undecided}} align="center" |'''10.0%'''
| {{party shading/Undecided}} align="center" |'''5.4%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103080459593791.pdf.htm Embrain Public]
| rowspan="2" | [[News1]]
| rowspan="2" align="center" | March 7-8, 2021 
| rowspan="2" align="center" | LI(M-VN)
| rowspan="2" align="center" | 1,009
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| align="center" | 38.7%
| {{party shading/People Party (South Korea)}} align="center" | '''46.2%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.5%'''
| {{party shading/Undecided}} align="center" |'''10.4%'''
| {{party shading/Undecided}} align="center" |'''3.2%'''
|-
| align="center" | –
| align="center" | 39.3%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''43.1%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.9%'''
| {{party shading/Undecided}} align="center" |'''12.3%'''
| {{party shading/Undecided}} align="center" |'''3.4%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103081131073670.pdf.htm WinG Korea]
| rowspan="2" | Asia Economy
| rowspan="2" align="center" | March 6-7, 2021 
| rowspan="2" align="center" | ARS(M-VN)
| rowspan="2" align="center" | 1,002
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| align="center" | 38.8%
| {{party shading/People Party (South Korea)}} align="center" | '''49.2%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''4.5%'''
| {{party shading/Undecided}} align="center" |'''5.4%'''
| {{party shading/Undecided}} align="center" |'''2.0%'''
|-
| align="center" | –
| align="center" | 39.5%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''49.3%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.9%'''
| {{party shading/Undecided}} align="center" |'''6.3%'''
| {{party shading/Undecided}} align="center" |'''2.0%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202104/FILE_202103070845125970.pdf.htm IPSOS]
| rowspan="2" | [[Korea JoongAng Daily|JoongAng Daily]]
| rowspan="2" align="center" | March 5-6, 2021 
| rowspan="2" align="center" | {{small|LI<br>(L-RDD 14.9% M-VN 85.1%)}}
| rowspan="2" align="center" | 1,004
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| align="center" | 41.6%
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''45.3%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.5%'''
| {{party shading/Undecided}} align="center" |'''10.6%'''
| {{party shading/Undecided}} align="center" |'''1.0%'''
|-
| align="center" | –
| align="center" | 39.8%
| {{party shading/People Party (South Korea)}} align="center" | '''47.3%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.2%'''
| {{party shading/Undecided}} align="center" |'''10.7%'''
| {{party shading/Undecided}} align="center" |'''0.9%'''
|- 
! colspan="3" |March 4, 2021
! colspan="11" |People Power Party's nomination
|- style="background:lightyellow;"
! colspan="3" |March 1, 2021
! colspan="11" |Democratic Party's nomination
|-
| rowspan="3" | [https://www.nesdc.go.kr/files/result/202103/FILE_202103020150350300.pdf.htm RnSearch]
| rowspan="3" | Daehan Economic
| rowspan="3" align="center" | February 25-26, 2021 
| rowspan="3" align="center" | ARS(M-VN)
| rowspan="3" align="center" | 818
| rowspan="3" align="center" | 95%, ±3.4%p
| align="center" | –
| align="center" | 34.1%
| {{party shading/People Party (South Korea)}} align="center" | '''36.7%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''16.3%'''
| {{party shading/Undecided}} align="center" |'''10.6%'''
| {{party shading/Undecided}} align="center" |'''2.0%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.8%'''
| align="center" | –
| align="center" | –
| align="center" | 35.2%
| {{party shading/Undecided}} align="center" |'''13.0%'''
| {{party shading/Undecided}} align="center" |'''12.8%'''
| {{party shading/Undecided}} align="center" |'''3.2%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.4%'''
| align="center" | –
| align="center" | 33.4%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''15.6%'''
| {{party shading/Undecided}} align="center" |'''13.1%'''
| {{party shading/Undecided}} align="center" |'''2.4%'''
|-
| rowspan="3" | [https://www.nesdc.go.kr/files/result/202103/FILE_202102181030093420.pdf.htm Hangil Research]
| rowspan="3" | [[Maeil Broadcasting Network|MBN]]
| rowspan="3" align="center" | February 15-16, 2021 
| rowspan="3" align="center" | ARS(M-VN)
| rowspan="3" align="center" | 807
| rowspan="3" align="center" | 95%, ±3.4%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''39.0%'''
| align="center" | –
| align="center" | –
| align="center" | 27.2%
| {{party shading/Undecided}} align="center" |'''20.5%'''
| {{party shading/Undecided}} align="center" |'''11.3%'''
| {{party shading/Undecided}} align="center" |'''1.9%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''39.5%'''
| align="center" | –
| align="center" | 27.0%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''18.1%'''
| {{party shading/Undecided}} align="center" |'''13.7%'''
| {{party shading/Undecided}} align="center" |'''1.7%'''
|-
| align="center" | –
| align="center" | 39.3%
| {{party shading/People Party (South Korea)}} align="center" | '''39.4%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''18.1%'''
| {{party shading/Undecided}} align="center" |'''13.7%'''
| {{party shading/Undecided}} align="center" |'''1.7%'''
|-
| rowspan="6" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102100225489530.pdf.htm IPSOS]
| rowspan="6" | [[Seoul Broadcasting System|SBS]]
| rowspan="6" align="center" | February 6-9, 2021 
| rowspan="6" align="center" | {{Small|LI<br>(L-RDD 10% M-VN 90%)}}
| rowspan="6" align="center" | 800
| rowspan="6" align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''43.7%'''
| align="center" | –
| align="center" | –
| align="center" | 33.7%
| {{party shading/Undecided}} align="center" |'''7.7%'''
| {{party shading/Undecided}} align="center" |'''14.5%'''
| {{party shading/Undecided}} align="center" |'''0.5%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''45.1%'''
| align="center" | –
| align="center" | 33.0%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''8.0%'''
| {{party shading/Undecided}} align="center" |'''13.4%'''
| {{party shading/Undecided}} align="center" |'''0.5%'''
|-
| align="center" | –
| align="center" | 40.6%
| {{party shading/People Party (South Korea)}} align="center" | '''43.5%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''3.7%'''
| {{party shading/Undecided}} align="center" |'''11.5%'''
| {{party shading/Undecided}} align="center" |'''0.6%'''
|-
| align="center" | 35.7%
| align="center" | –
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''36.3%'''
| {{party shading/Undecided}} align="center" |'''7.6%'''
| {{party shading/Undecided}} align="center" |'''20.2%'''
| {{party shading/Undecided}} align="center" |'''0.3%'''
|-
| align="center" | 35.3%
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''37.7%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''7.2%'''
| {{party shading/Undecided}} align="center" |'''19.5%'''
| {{party shading/Undecided}} align="center" |'''0.2%'''
|-
| align="center" | 33.0%
| align="center" | –
| {{party shading/People Party (South Korea)}} align="center" | '''46.9%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''4.4%'''
| {{party shading/Undecided}} align="center" |'''15.4%'''
| {{party shading/Undecided}} align="center" |'''0.4%'''
|-
| rowspan="6" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102100238058221.pdf.htm KRi]
| rowspan="6" | [[Munhwa Broadcasting Corporation|MBC]]
| rowspan="6" align="center" | February 8-9, 2021 
| rowspan="6" align="center" | LI(M-VN)
| rowspan="6" align="center" | 804
| rowspan="6" align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''46.0%'''
| align="center" | –
| align="center" | –
| align="center" | 33.7%
| {{party shading/Undecided}} align="center" |'''0.2%'''
| {{party shading/Undecided}} align="center" |'''18.4%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''45.3%'''
| align="center" | –
| align="center" | 36.1%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.7%'''
| {{party shading/Undecided}} align="center" |'''16.3%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''41.9%'''
| align="center" | 41.4%
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.4%'''
| {{party shading/Undecided}} align="center" |'''14.6%'''
| {{party shading/Undecided}} align="center" |'''1.8%'''
|-
| align="center" | 33.9%
| align="center" | –
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''37.9%'''
| {{party shading/Undecided}} align="center" |'''0.7%'''
| {{party shading/Undecided}} align="center" |'''26.4%'''
| {{party shading/Undecided}} align="center" |'''1.1%'''
|-
| align="center" | 31.0%
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''41.8%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.5%'''
| {{party shading/Undecided}} align="center" |'''25.0%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| align="center" | 29.3%
| align="center" | –
| {{party shading/People Party (South Korea)}} align="center" | '''44.7%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.9%'''
| {{party shading/Undecided}} align="center" |'''23.4%'''
| {{party shading/Undecided}} align="center" |'''1.8%'''
|-
| rowspan="6" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102090321062280.pdf.htm Realmeter]
| rowspan="6" | [[Traffic Broadcasting System|TBS]], [[YTN]]
| rowspan="6" align="center" | February 7-8, 2021 
| rowspan="6" align="center" | {{small|LI 50%, ARS 50%<br>(M-RDD 80%, L-RDD 20%)}}
| rowspan="6" align="center" | 1,016
| rowspan="6" align="center" |95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''39.7%'''
| align="center" | –
| align="center" | –
| align="center" | 34.0%
| {{party shading/Undecided}} align="center" |'''6.2%'''
| {{party shading/Undecided}} align="center" |'''16.8%'''
| {{party shading/Undecided}} align="center" |'''3.3%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''38.9%'''
| align="center" | 36.3%
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''5.7%'''
| {{party shading/Undecided}} align="center" |'''15.9%'''
| {{party shading/Undecided}} align="center" |'''3.2%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''40.6%'''
| align="center" | –
| align="center" | 29.7%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''7.2%'''
| {{party shading/Undecided}} align="center" |'''18.5%'''
| {{party shading/Undecided}} align="center" |'''4.0%'''
|-
| align="center" | 29.1%
| align="center" | –
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''34.4%'''
| {{party shading/Undecided}} align="center" |'''7.5%'''
| {{party shading/Undecided}} align="center" |'''26.3%'''
| {{party shading/Undecided}} align="center" |'''2.7%'''
|-
| align="center" | 28.2%
| align="center" | –
| {{party shading/People Party (South Korea)}} align="center" | '''40.4%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''5.5%'''
| {{party shading/Undecided}} align="center" |'''23.0%'''
| {{party shading/Undecided}} align="center" |'''3.0%'''
|-
| align="center" | 30.6%
| align="center" | –
| align="center" | –
| {{party shading/People Power Party (South Korea)}} align="center" | '''32.7%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''5.5%'''
| {{party shading/Undecided}} align="center" |'''23.0%'''
| {{party shading/Undecided}} align="center" |'''3.0%'''
|-
| rowspan="3" | [https://nesdc.go.kr/files/result/202102/FILE_202102080444334201.pdf.htm Embrain Public]
| rowspan="3" | [[Munhwa Ilbo]]
| rowspan="3" align="center" | February 5-6, 2021 
| rowspan="3" align="center" | LI(M-VN)
| rowspan="3" align="center" | 800
| rowspan="3" align="center" |95%, ±3.46%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''43.1%'''
| align="center" | –
| align="center" | –
| align="center" | 36.1%
| {{party shading/Undecided}} align="center" |'''2.5%'''
| {{party shading/Undecided}} align="center" |'''16.7%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| align="center" | –
| align="center" | 37.7%
| {{party shading/People Party (South Korea)}} align="center" | '''46.6%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.5%'''
| {{party shading/Undecided}} align="center" |'''12.4%'''
| {{party shading/Undecided}} align="center" |'''1.8%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''42.3%'''
| align="center" | 39.3%
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.6%'''
| {{party shading/Undecided}} align="center" |'''14.4%'''
| {{party shading/Undecided}} align="center" |'''2.4%'''
|-
| rowspan="6" | [https://nesdc.go.kr/files/result/202102/FILE_202102080444334201.pdf.htm Hankook Research]
| rowspan="6" | [[Hankook Ilbo]]
| rowspan="6" align="center" | February 4-6, 2021 
| rowspan="6" align="center" | LI(M-VN)
| rowspan="6" align="center" | 800
| rowspan="6" align="center" |95%, ±3.5%p
| align="center" | –
| align="center" | 41.1%
| align="center" | –
| align="center" | –
| style="background: rgba(230, 30, 43, 0.5)" align="center" | '''41.3%'''
| {{party shading/Undecided}} align="center" |'''9.0%'''
| {{party shading/Undecided}} align="center" |'''2.7%'''
| {{party shading/Undecided}} align="center" |'''6.0%'''
|-
| align="center" | –
| align="center" | 40.8%
| align="center" | –
| style="background: rgba(230, 30, 43, 0.5)" align="center" | '''41.8%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''9.0%'''
| {{party shading/Undecided}} align="center" |'''1.9%'''
| {{party shading/Undecided}} align="center" |'''6.6%'''
|-
| align="center" | –
| align="center" | 39.2%
| style="background: rgba(234, 85, 4, 0.5)" align="center" | '''46.0%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''7.4%'''
| {{party shading/Undecided}} align="center" |'''2.2%'''
| {{party shading/Undecided}} align="center" |'''5.1%'''
|-
| align="center" | 33.5%
| align="center" | –
| align="center" | –
| align="center" | –
| style="background: rgba(230, 30, 43, 0.5)" align="center" | '''44.9%'''
| {{party shading/Undecided}} align="center" |'''11.6%'''
| {{party shading/Undecided}} align="center" |'''3.7%'''
| {{party shading/Undecided}} align="center" |'''6.2%'''
|-
| align="center" | 32.5%
| align="center" | –
| align="center" | –
| style="background: rgba(230, 30, 43, 0.5)" align="center" | '''46.0%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''11.5%'''
| {{party shading/Undecided}} align="center" |'''3.7%'''
| {{party shading/Undecided}} align="center" |'''6.3%'''
|-
| align="center" | 31.2%
| align="center" | –
| style="background: rgba(234, 85, 4, 0.5)" align="center" | '''50.4%'''
| align="center" | –
| align="center" | –
| {{party shading/Undecided}} align="center" |'''9.5%'''
| {{party shading/Undecided}} align="center" |'''3.1%'''
| {{party shading/Undecided}} align="center" |'''5.8%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102030459062560.pdf.htm Jowon C&I]
| rowspan="2" |Sisa Journal
| rowspan="2" align="center" | February 1-2, 2021
| rowspan="2" align="center" | ARS(M-VN)
| rowspan="2" align="center" | 1,000
| rowspan="2" align="center" |95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''41.7%'''
| align="center" | –
| align="center" | –
| align="center"| 33.7%
| {{party shading/Undecided}} align="center" |'''9.9%'''
| {{party shading/Undecided}} align="center" | '''10.0%'''
| {{party shading/Undecided}} align="center" | '''4.8%'''
|-
| align="center" |–
| {{party shading/Democratic Party of Korea}} align="center" |'''41.0%'''
| align="center" |36.8%
| align="center" |–
| align="center" |–
| {{party shading/Undecided}} align="center" |'''7.8%'''
| {{party shading/Undecided}} align="center" |'''9.5%'''
| {{party shading/Undecided}} align="center" |'''4.9%'''
|-
! colspan="14" |For more information, visit the [https://www.nesdc.go.kr/portal/main.do National Election Survey Deliberation Committee]<!-- Recommend to include "visit the National Election Survey Deliberation Committee". When publishing an election-related opinion poll in South Korea, name of the poll requester, name of the polling agency, the date of the poll, and the phrase "visit the website of the National Election Poll Deliberation Committee" must all be included. The absence of any of these may violate the Korean Public Official Election Act. There are no such regulations in US law, but I recommended to include this phrase. -->
|}
{{Hidden end}}
{{Hidden begin |title=Virtual polling (three-way)}}
{| class="wikitable" style="font-size:90%;"
|- valign=bottom
! Poll source
! Client
! Date(s)<br>administered
! Method
! Sample<br>size
! Margin<br>of Error
! style="width:75px;" | Woo<br>Sang-ho
! style="width:75px;" | Park<br>Young-sun
! style="width:75px;" | Ahn<br>Cheol-soo
! style="width:75px;" | Oh<br>Se-hoon
! style="width:78px;" | Na<br>Kyoung-won
! Others
! None
! Don't know<br>or no answer
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103150214379490.pdf.htm PNR]
| Mirae Hankook Research/<br>[[Aju Business Daily]]
| align="center" | March 14, 2021 
| align="center" | {{small|ARS<br>(M-VN 84% L-RDD 16%)}}
| align="center" | 806
| align="center" | 95%, ±3.5%p
| align="center" | –
| align="center" | 30.7%
| align="center" | 26.1%
| {{party shading/People Power Party (South Korea)}} align="center" | '''34.7%'''
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.7%'''
| {{party shading/Undecided}} align="center" |'''4.8%'''
| {{party shading/Undecided}} align="center" |'''1.0%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103150433334300.pdf.htm Kanta Korea]
| [[The Chosun Ilbo]]/[[TV Chosun]]
| align="center" | March 13, 2021 
| align="center" | ARS(M-VN)
| align="center" | 806
| align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''28.8%'''
| align="center" | 27.2%
| align="center" | 19.9%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.1%'''
| {{party shading/Undecided}} align="center" |'''5.0%'''
| {{party shading/Undecided}} align="center" |'''17.0%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103140419233060.pdf.htm PNR]
| Mirae Hankook Research/<br>Money Today
| align="center" | March 13, 2021 
| align="center" | ARS(M-VN 81% L-RDD 19%)
| align="center" | 802
| align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''33.0%'''
| align="center" | 32.5%
| align="center" | 27.9%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''3.3%'''
| {{party shading/Undecided}} align="center" |'''2.1%'''
| {{party shading/Undecided}} align="center" |'''1.2%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103100307091200.pdf.htm Hankook Research]
| [[Korean Broadcasting System|KBS]]
| align="center" | March 8-9, 2021 
| align="center" | LI(M-VN)
| align="center" | 800
| align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.0%'''
| align="center" | 25.4%
| align="center" | 24.0%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''2.1%'''
| {{party shading/Undecided}} align="center" |'''8.0%'''
| {{party shading/Undecided}} align="center" |'''5.5%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103080459593791.pdf.htm Embrain Public]
| [[News1]]
| align="center" | March 7-8, 2021 
| align="center" | LI(M-VN)
| align="center" | 1,009
| align="center" | 95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.8%'''
| align="center" | 26.0%
| align="center" | 25.4%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.4%'''
| {{party shading/Undecided}} align="center" |'''9.3%'''
| {{party shading/Undecided}} align="center" |'''2.1%'''
|-
| [https://www.nesdc.go.kr/files/result/202104/FILE_202103070845125970.pdf.htm IPSOS]
| [[Korea JoongAng Daily|JoongAng Daily]]
| align="center" | March 5-6, 2021 
| align="center" | {{small|LI<br>(L-RDD 14.9% M-VN 85.1%)}}
| align="center" | 1,004
| align="center" | 95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.8%'''
| align="center" | 24.2%
| align="center" | 26.4%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''1.7%'''
| {{party shading/Undecided}} align="center" |'''9.3%'''
| {{party shading/Undecided}} align="center" |'''2.5%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202103/FILE_202102181030093420.pdf.htm Hangil Research]
| rowspan="2" | [[Maeil Broadcasting Network|MBN]]
| rowspan="2" align="center" | February 15-16, 2021 
| rowspan="2" align="center" | ARS(M-VN)
| rowspan="2" align="center" | 804
| rowspan="2" align="center" | 95%, ±3.4%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''37.8%'''
| align="center" | 27.9%
| align="center" | –
| align="center" | 20.8%
| {{party shading/Undecided}} align="center" |'''6.8%'''
| {{party shading/Undecided}} align="center" |'''5.2%'''
| {{party shading/Undecided}} align="center" |'''1.6%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''39.3%'''
| align="center" | 31.3%
| align="center" | 16.1%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''6.6%'''
| {{party shading/Undecided}} align="center" |'''5.6%'''
| {{party shading/Undecided}} align="center" |'''1.0%'''
|-
| rowspan="4" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102100238058221.pdf.htm KRi]
| rowspan="4" | [[Munhwa Broadcasting Corporation|MBC]]
| rowspan="4" align="center" | February 8-9, 2021 
| rowspan="4" align="center" | LI(M-VN)
| rowspan="4" align="center" | 804
| rowspan="4" align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''39.7%'''
| align="center" | 27.1%
| align="center" | –
| align="center" | 19.2%
| {{party shading/Undecided}} align="center" |'''0.4%'''
| {{party shading/Undecided}} align="center" |'''12.4%'''
| {{party shading/Undecided}} align="center" |'''1.3%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''38.7%'''
| align="center" | 27.8%
| align="center" | 19.6%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.1%'''
| {{party shading/Undecided}} align="center" |'''12.8%'''
| {{party shading/Undecided}} align="center" |'''1.0%'''
|-
| align="center" |28.1%
| align="center" | –
| {{party shading/People Party (South Korea)}} align="center" | '''30.0%'''
| align="center" | –
| align="center" | 21.9%
| {{party shading/Undecided}} align="center" |'''0.5%'''
| {{party shading/Undecided}} align="center" |'''18.2%'''
| {{party shading/Undecided}} align="center" |'''1.3%'''
|-
| align="center" |28.1%
| align="center" | –
| {{party shading/People Party (South Korea)}} align="center" | '''31.2%'''
| align="center" | 20.3%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''0.6%'''
| {{party shading/Undecided}} align="center" |'''18.6%'''
| {{party shading/Undecided}} align="center" |'''1.1%'''
|-
| rowspan="2" | [https://www.nesdc.go.kr/files/result/202102/FILE_202102090321062280.pdf.htm Realmeter]
| rowspan="2" | [[Traffic Broadcasting System|TBS]], [[YTN]]
| rowspan="2" align="center" | February 7-8, 2021 
| rowspan="2" align="center" | {{small|LI 50%, ARS 50%<br>(M-RDD 80%, L-RDD 20%)}}
| rowspan="2" align="center" | 1,016
| rowspan="2" align="center" | 95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''37.5%'''
| align="center" | 22.7%
| align="center" | –
| align="center" | 25.0%
| {{party shading/Undecided}} align="center" |'''3.6%'''
| {{party shading/Undecided}} align="center" |'''9.9%'''
| {{party shading/Undecided}} align="center" |'''1.4%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''37.7%'''
| align="center" | 26.7%
| align="center" | 18.7%
| align="center" | –
| {{party shading/Undecided}} align="center" |'''4.2%'''
| {{party shading/Undecided}} align="center" |'''11.4%'''
| {{party shading/Undecided}} align="center" |'''1.3%'''
|-
| rowspan="4" | [https://nesdc.go.kr/files/result/202102/FILE_202102080444334201.pdf.htm Hankook Research]
| rowspan="4" | [[Hankook Ilbo]]
| rowspan="4" align="center" | February 4-6, 2021
| rowspan="4" align="center" | LI(M-VN)
| rowspan="4" align="center" | 800
| rowspan="4" align="center" | 95%, ±3.5%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''35.7%'''
| align="center" | 27.0%
| align="center" | –
| align="center" | 22.8%
| {{party shading/Undecided}} align="center" | '''6.8%'''
| {{party shading/Undecided}} align="center" | '''1.2%'''
| {{party shading/Undecided}} align="center"| '''6.4%'''
|-
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''37.0%'''
| align="center" | 29.6%
| align="center" | 19.0%
| align="center" | –
| {{party shading/Undecided}} align="center" | '''6.6%'''
| {{party shading/Undecided}} align="center" | '''1.7%'''
| {{party shading/Undecided}} align="center"| '''6.1%'''
|-
| align="center" | 26.7%
| align="center" | –
| style="background-color: rgba(234, 85, 4, 0.5)" align="center" | '''29.6%'''
| align="center" | –
| align="center" | 24.7%
| {{party shading/Undecided}} align="center" | '''8.2%'''
| {{party shading/Undecided}} align="center" | '''2.9%'''
| {{party shading/Undecided}} align="center"| '''5.9%'''
|-
| align="center" | 27.7%
| align="center" | –
| style="background-color: rgba(234, 85, 4, 0.5)" align="center" | '''34.5%'''
| align="center" | 21.8%
| align="center" | –
| {{party shading/Undecided}} align="center" | '''7.2%'''
| {{party shading/Undecided}} align="center" | '''2.1%'''
| {{party shading/Undecided}} align="center"| '''6.7%'''
|-
| [https://www.nesdc.go.kr/files/result/202102/FILE_202102030459062560.pdf.htm Jowon C&I]
|Sisa Journal
| align="center"| February 1-2, 2021
| align="center"| ARS(M-VN)
| align="center"| 1,000
| align="center"| 95%, ±3.1%p
| align="center" | –
| {{party shading/Democratic Party of Korea}} align="center" | '''38.4%'''
| align="center" | 21.6%
| align="center" | –
| align="center" | 22.6%
| {{party shading/Undecided}} align="center" | '''4.5%'''
| {{party shading/Undecided}} align="center" | '''8.3%'''
| {{party shading/Undecided}} align="center"| '''4.6%'''
|-
! colspan="14" |For more information, visit the [https://www.nesdc.go.kr/portal/main.do National Election Survey Deliberation Committee]<!-- Recommend to include "visit the National Election Survey Deliberation Committee". When publishing an election-related opinion poll in South Korea, name of the poll requester, name of the polling agency, the date of the poll, and the phrase "visit the website of the National Election Poll Deliberation Committee" must all be included. The absence of any of these may violate the Korean Public Official Election Act. There are no such regulations in US law, but I recommended to include this phrase. -->
|}
{{Hidden end}}
{{Hidden|Polling method|*ARS: Automatic Response System, a robocall method similar to [[IVR]]
*LI: Live interview
*M-VN: Poll that surveyed '''[[Mobile phone]]''' users with '''[[Virtual number]]'''
*M-RDD: Poll that surveyed '''[[Mobile phone]]''' users with '''[[Random digit dialing]]'''
*L-RDD: Poll that surveyed '''[[Landline]]''' users with '''[[Random digit dialing]]'''}}

=== Results ===
{{Election box begin |title=2021 Seoul mayoral by-election}}
{{Election box candidate with party link
  |party      = Democratic Party of Korea
  |candidate  = Park Young-sun
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = People Power Party (South Korea)
  |candidate  = Oh Se-hoon
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Basic Income Party
  |candidate  = Shin Ji-hye
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = National Revolutionary Dividends Party
  |candidate  = Huh Kyung-young
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Mirae Party
  |candidate  = Oh Tae-yang
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Minsaeng Party
  |candidate  = Lee Su-bong
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate
  |party      = New Liberal Democratic Union
  |candidate  = Bae Yeong-gyu
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Women's Party (South Korea)
  |candidate  = Kim Jin-ah
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Progressive Party (South Korea, 2017)
  |candidate  = Song Myeong-suk
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Independent (politics)
  |candidate  = Chung Dong-hui
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Independent (politics)
  |candidate  = Lee Do-yeop
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Independent (politics)
  |candidate  = Shin Ji-ye
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box majority <!-- Democratic & People Power -->
   |votes      = TBD
   |percentage = TBD
   |change     = TBD
 }}
{{Election box turnout
   |votes      = TBD
   |percentage = TBD
   |change     = TBD
 }}
{{Election box registered electors
   |reg. electors = 8,425,869
|change = +0.5
}}
{{Election box end}}

== Mayor of Busan ==
{{Infobox election
 | election_name      = 2021 Busan mayoral by-election
 | type               = By-election
 | country            = South Korea
 | seats_for_election = Busan Metropolitan Mayor.<br />Elected by simple majority using [[first past the post]].<br />Triggered by resignation of incumbent
 | ongoing            = yes
 | previous_election  = 2018 South Korean local elections
 | previous_year      = 2018
 | next_election      = 2022 South Korean local elections
 | next_year          = 2022
 | election_date      = {{Start date|2021|04|07|df= y}}
 <!-- Democratic Party -->
 | candidate1         = [[Kim Young-choon]]
 | image1             = Kim young-chun 2020.png
 | party1             = Democratic Party of Korea
 | last_election1     = -
 | popular_vote1      = -
 | percentage1        = -
  <!-- People Power Party -->
 | candidate2         = [[Park Hyung-joon]]
 | image2             =  
 | party2             = People Power Party (South Korea)
 | last_election2     = -
 | popular_vote2      = -
 | percentage2        = -

 | title              = Mayor of Busan
 | posttitle          = Subsequent Mayor of Busan
 | before_election    = [[Oh Keo-don]]
 | before_party       = Democratic Party of Korea
 | after_election     =
 | after_party        = 
 | map_image          = 
 | map_size           = 
 | map_alt            = 
 | map                = 
 | map_caption        =
}}
=== Primary ===
==== Democratic Party ====
On 6 March 2021, [[Kim Young-choon]] won Democratic preselection for the Busan mayorship, defeating [[Byeon Sung-wan]] and [[Park In-young (politician)|Park In-young]].<ref>{{cite news |date= 6 March 2021|title= 민주당 부산시장 보선 후보에 김영춘 확정…경선서 67.74% 압승|url= https://www.yna.co.kr/view/AKR20210306050400051?input=1195m|access-date= 7 March 2021}}</ref>

===== Candidates =====
* [[Byeon Sung-wan]], [[Mayor of Busan|Acting Mayor of Busan]]<ref>{{Cite web|last=김선호|date=28 January 2021|title=변성완 부산 보선 출마선언 "초보 운전자에게 시정 못 맡겨"|url=https://www.yna.co.kr/view/AKR20210128089800051|url-status=live|access-date=25 February 2021|website=[[Yonhap News Agency]]|language=ko}}</ref>
*[[Kim Young-choon]], Former [[Ministry of Oceans and Fisheries|Minister of Oceans and Fisheries]]<ref>{{Cite web|last=전석우|date=12 January 2021|title=[영상] 민주당 첫 부산시장 출마 선언…김영춘 "부산 운명 바꿀것"|url=https://www.yna.co.kr/view/MYH20210112016000704|url-status=live|access-date=25 February 2021|website=[[Yonhap News Agency]]|language=ko}}</ref>
*[[Park In-young (politician)|Park In-young]], Former Speaker of the [[Busan Metropolitan Council]]<ref>{{Cite web|last=노준철|date=18 January 2021|title=박인영 출마 선언 “새로운 시민시대 열자”|url=https://news.kbs.co.kr/news/view.do?ncd=5097648|url-status=live|access-date=25 February 2021|website=[[KBS News]]|language=ko}}</ref>
<gallery mode="packed" heights="160">
File:Democratic Party of Korea, Symbol application 3.svg|{{center|[[Mayor of Busan|Acting Mayor of Busan]]<br/>'''[[Byeon Sung-wan]]'''}}
File:Kim young-chun 2020.png|{{Center|Former [[Ministry of Oceans and Fisheries|Minister of Oceans and Fisheries]]<br/>'''[[Kim Young-choon]]'''}}
File:Democratic Party of Korea, Symbol application 3.svg|{{center|Former Speaker of the [[Busan Metropolitan Council]]<br/>'''[[Park In-young (politician)|Park In-young]]'''}}  
</gallery>

==== People Power Party ====
On 4 March 2021, [[Park Hyung-joon]] won PPP [[preselection]] for the Busan mayorship, defeating [[Park Seong-hun (politician)|Park Seong-hun]] and [[Lee Un-ju]].<ref>{{cite news |date= 4 March 2021|title= [2보] 국민의힘 서울시장 후보에 오세훈…부산은 박형준|url= https://www.yna.co.kr/view/AKR20210304043600001?input=1195m|access-date= 5 March 2021}}</ref>

===== Candidates =====
* [[Park Min-sik]], Former Member of the [[National Assembly (South Korea)|National Assembly]]<ref>{{cite news |last1=김정우 |title=野 박민식 부산시장 출마 선언…"3050세대 집중 공략" |url=http://news.tvchosun.com/site/data/html_dir/2020/11/09/2020110990075.html|access-date=27 February 2021 |work=[[TV Chosun]] |date=9 November 2020 |language=ko}}</ref>
* [[Park Hyung-joon]], Former Professor of the [[Dong-a University]]<ref>{{cite news |last1=조원진 |title=박형준, 부산시장 출마 선언···"혁신이 물결치는 도시 만들겠다" |url=https://www.sedaily.com/NewsView/1ZBOYXUN73 |access-date=27 February 2021 |work=Seoul Economy Daily |date=15 December 2020 |language=ko}}</ref>
* [[Lee Un-ju]], Former Member of the [[National Assembly (South Korea)|National Assembly]]<ref>{{cite news |last1=여주연 |title=부산시장 출마선언하는 이언주 전 의원 |url=https://www.news1.kr/photos/view/?4533120 |access-date=27 February 2021 |work=[[News1]] |date=17 December 2020}}</ref>
* [[Park Seong-hun (politician)|Park Seong-hun]], Former Vice Mayor of [[Busan]]<ref>{{cite news |last1=성상훈 |title=박성훈, 부산시장 출마선언…"부산에 '실리콘 비치' 만들겠다" |url=https://www.hankyung.com/politics/article/202101143923i |access-date=27 February 2021 |work=[[Korea Economic Daily]] |date=14 January 2021}}</ref>
<gallery mode="packed" heights="160">
File:People Power Party (South Korea), signature 1.svg|{{center|Former Member of the [[National Assembly (South Korea)|National Assembly]]<br/>'''[[Park Min-sik]]'''}}
File:People Power Party (South Korea), signature 1.svg|{{Center|Former Professor of the [[Dong-a University]]<br/>'''[[Park Hyung-joon]]'''}}
File:이언주.png|{{Center|Former Member of the [[National Assembly (South Korea)|National Assembly]]<br/>'''[[Lee Un-ju]]'''}}
File:People Power Party (South Korea), signature 1.svg|{{center|Former Vice Mayor of [[Busan]]<br/>'''[[Park Seong-hun (politician)|Park Seong-hun]]'''}}  
</gallery>

=== List of registered candidates ===
{| class="wikitable"
! # !! Name !! Party !! Date of birth !! Career !! Notes
|-
| 1 || [[Kim Young-choon]] || [[Democratic Party of Korea|Democratic]] || {{birth date and age|1962|2|5|df=yes}} || Former Member of the [[National Assembly (South Korea)|National Assembly]]<br>Former [[Ministry of Oceans and Fisheries|Minister of Oceans and Fisheries]] (2017-2019)<br>Former Secretary-General of the National Assembly (2020) ||
|-
| 2 || [[Park Hyung-joon]] || [[People Power Party (South Korea)|PPP]] || {{birth date and age|1960|1|19|df=yes}} || Former Professor at [[Dong-a University]] (1991-2021)<br>Former Member of the National Assembly for [[Suyeong District|Suyeong]] (2004-2008)<br>Former [[Senior Presidential Secretary|Senior Secretary to the President for Political Affairs]] (2009-2010)<br>Former Secretary-General of the National Assembly (2014-2016) ||
|-
| 6 || [[Sohn Sang-woo]] || [[Mirae Party|Mirae]] || {{birth date and age|1981|12|16|df=yes}} || Head of the Mirae Party for [[Busan]] ||
|-
| 7 || [[Bae Joon-hyun]] || [[Minsaeng Party|Minsaeng]] || {{birth date and age|1973|2|8|df=yes}} || Head of the Minsaeng Party for Busan ||
|-
| 8 || [[Jeong Kyu-jae]] || [[Freedom and Democracy Party (South Korea)|FDP]] || {{birth date and age|1957|1|12|df=yes}} || Former Chief Editor of ''[[Korea Economic Daily]]''<br>Founder and former Chief of ''[[Pennmike]]'' ||
|-
| 9 || [[Roh Jung-hyun]] || [[Progressive Party (South Korea, 2020)|Progressive]] || {{birth date and age|1978|1|28|df=yes}} || Former Member of the [[Yeonje District]] Council (2010-2014)<br>Head of the Progressive Party for Busan ||
|-
! colspan="6" |Source: [http://info.nec.go.kr/electioninfo/electionInfo_report.xhtml National Election Commission]
|}

=== Results ===
{{Election box begin |title=2021 Busan mayoral by-election}}
{{Election box candidate with party link
  |party      = Democratic Party of Korea
  |candidate  = Kim Young-choon
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = People Power Party (South Korea)
  |candidate  = Park Hyeong-jun
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Mirae Party
  |candidate  = Son Sang-woo
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Minsaeng Party
  |candidate  = Bae Jun-hyeon
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate
  |party      = Liberal Democrats
  |candidate  = Chung Kyu-jae
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box candidate with party link
  |party      = Progressive Party (South Korea, 2017)
  |candidate  = Roh Jeong-hyeon
  |votes      = TBD
  |percentage = TBD
  |change     = TBD
}}
{{Election box majority <!-- Democratic & People Power -->
   |votes      = TBD
   |percentage = TBD
   |change     = TBD
 }}
{{Election box turnout
   |votes      = TBD
   |percentage = TBD
   |change     = TBD
 }}
{{Election box registered electors
   |reg. electors = 2,936,301
|change = -0.1
}}
{{Election box end}}

== Municipal Mayor ==
=== Mayor of Nam District ===
{{Election box begin no change |title=2021 Nam District mayoral by-election}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Seok-gyeom
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Seo Dong-wook
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Progressive Party (South Korea, 2017)
  |candidate  = Kim Jin-seok
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 271,967
}}
{{Election box end}}
=== Mayor of Uiryeong County ===
{{Election box begin no change |title=2021 Uiryeong County mayoral by-election}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Chung-gyu
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Oh Tae-wan
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Progressive Party (South Korea, 2017)
  |candidate  = Kim Jin-seok
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Oh Yong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Kim Chang-hwan
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 24,452
}}
{{Election box end}}
== Member of Metropolitan Council ==
=== Seoul Metropolitan Council ===
{{Election box begin no change |title=2021 Seoul Metropolitan Council by-election: Gangbuk 1st}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Seung-sik
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Lee Jong-hwan
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 79,833
}}
{{Election box end}}
=== Gyeonggi Metropolitan Council ===
{{Election box begin no change |title=2021 Gyeonggi Metropolitan Council by-election: Guri 1st}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Shin Dong-hwa
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Paik Hyeon-jong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 108,996
}}
{{Election box end}}
=== North Chungcheong Metropolitan Council ===
{{Election box begin no change |title=2021 North Chungcheong Metropolitan Council by-election: Boeun}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Gi-jun
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Won Gap-hui
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Park Kyeong-suk
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 32,252
}}
{{Election box end}}
=== South Jeolla Metropolitan Council ===
{{Election box begin no change |title=2021 South Jeolla Metropolitan Council by-election: Suncheon 1st}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Han Chun-ok
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Ju Yun-sik
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 54,278
}}
{{Election box end}}
{{Election box begin no change |title=2021 South Jeolla Metropolitan Council by-election: Goheung 2nd}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Park Seon-jun
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Chung Sun-yeol
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 33,196
}}
{{Election box end}}
=== South Gyeongsang Metropolitan Council ===
{{Election box begin no change |title=2021 South Gyeongsang Metropolitan Council by-election: Goseong 1st}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Ryu Jeong-yeol
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Paik Su-myeong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Lee Woo-yeong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 26,002
}}
{{Election box end}}
{{Election box begin no change |title=2021 South Gyeongsang Metropolitan Council by-election: Uiryeong}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Chung Kwon-yong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Son Tae-yeong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 26,676
}}
{{Election box end}}
{{Election box begin no change |title=2021 South Gyeongsang Metropolitan Council by-election: Hamyang}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Chung Jae-gak
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Park Hui-gyu
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Kim Jae-woong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 39,058
}}
{{Election box end}}
== Member of Municipal Council ==
=== Seoul ===
{{Election box begin no change |title=2021 Yeongdeungpo Council by-election: F electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Yang Songi
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Cha In-yeong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 42,282
}}
{{Election box end}}
{{Election box begin no change |title=2021 Songpa Council by-election: D electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Bae Shin-jeong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Kim Sun-ae
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Mirae Party
  |candidate  = Choi ji-seon
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 73,776
}}
{{Election box end}}
=== Ulsan ===
{{Election box begin no change |title=2021 Ulju Council by-election: B electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Ki-rak
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Park Ki-hong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 89,803
}}
{{Election box end}}
=== Gyeonggi ===
{{Election box begin no change |title=2021 Paju Council by-election: A electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Son Seong-ik
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Park Su-yeon
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Progressive Party (South Korea, 2017)
  |candidate  = Kim Yeong-jung
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 139,842
}}
{{Election box end}}
=== South Chungcheong ===
{{Election box begin no change |title=2021 Yesan Council by-election: D electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Lee Heung-yeop
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Hong Won-pyo
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Shin Hyeon-mo
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Lee Kyeong-il
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = In Hui-yeol
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 17,249
}}
{{Election box end}}
=== North Jeolla ===
{{Election box begin no change |title=2021 Gimje Council by-election: B electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Kim Seung-il
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Kim Seong-bae
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Moon Byeong-seon
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Choi Hoon
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 23,807
}}
{{Election box end}}
=== South Jeolla ===
{{Election box begin no change |title=2021 Boseong Council by-election: C electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Cho Yeong-nam
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Kim Mi-yeol
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Yoon Jeong-jae
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 8,641
}}
{{Election box end}}
=== South Gyeongsang ===
{{Election box begin no change |title=2021 Uiryeong Council by-election: D electoral district}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Cha Seong-gil
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = Independent (politics)
  |candidate  = Yoon Byeong-yeol
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 5,613
}}
{{Election box end}}
{{Election box begin no change |title=2021 Haman Council by-election: C electoral district}}
{{Election box candidate with party link no change
  |party      = Democratic Party of Korea
  |candidate  = Cho Ho-gi
  |votes      = TBD
  |percentage = TBD
}}
{{Election box candidate with party link no change
  |party      = People Power Party (South Korea)
  |candidate  = Hwang Cheol-yong
  |votes      = TBD
  |percentage = TBD
}}
{{Election box turnout no change
   |votes      = TBD
   |percentage = TBD
 }}
{{Election box registered electors no change
   |reg. electors = 21,285
}}
{{Election box end}}


== References ==
{{Reflist}}
{{South Korean elections}}

[[Category:By-elections to the National Assembly (South Korea)|2021]]
[[Category:2021 in South Korea]]
[[Category:2021 elections in Asia|South Korea]]