K League
K League is South Korea's professional football league. It includes the first division K League 1 and the second division K League 2. Clubs competing in the K League have won a record total of twelve AFC Champions League titles, the top continental competition for Asian clubs.
History
Until the 1970s, South Korean football operated two major football leagues, the National Semi-professional Football League and the National University Football League, but these were not professional leagues, and footballers could not focus solely on football. In 1979, however, the Korea Football Association president Choi Soon-young planned to establish a professional football league, and founded South Korea's first professional football club, Hallelujah FC, the following year. After the South Korean professional baseball league KBO League was founded in 1982, the KFA was aware of crisis about the popularity of football. In 1983, it urgently founded the Korean Super League with two professional clubs and three semi-professional clubs to professionalize South Korean football. Then, the Super League accomplished its purpose after existing clubs were also converted into professional clubs and new professional clubs joined the league. In its early years, it also used a promotion system by granting qualification to the semi-professional League winners.However, the number of spectators consistently decreased despite KFA's effort, and so the professional league, renamed as the Korean Professional Football League, operated a home-and-away system to interest fans since 1987. On 30 July 1994, the Professional League Committee under KFA was independent of the association, and renamed as the "Korean Professional Football Federation". In 1996, the South Korean government and the Football Federation introduced a decentralization policy to proliferate the popularity of football nationally in preparation for the 2002 FIFA World Cup, which they wanted to host. Several clubs located in the capital Seoul moved to other cities according to the new policy, but this was abolished after only three years and is regarded as a failed policy because it gave up the most populous city in South Korea. In 1998, the league was renamed again as current K League.
The league adopted its current format by abolishing the K League Championship and the Korean League Cup after the 2011 season, and being split into two divisions in 2013. The first division's name was the K League Classic, and the second division's name was the K League Challenge at the time. The fact that both the first and the second divisions had very similar names caused some degree of confusion and controversy. Beginning with the 2018 season, both divisions were renamed the K League 1 and the K League 2 respectively.
In February 2021, an OTT service for international markets called K League TV was officially launched.
Structure
Below K League 1 is the second-tier K League 2, and both form the K League as professional championships. Under them, there are two semi-professional leagues and three amateur leagues. At present, promotion and relegation exists within each of the three levels but clubs from K3 and below cannot be promoted to the K League. However, the KFA has announced plans to combine the three promotion-relegation systems into one from 2027.Since 2021, K League 1 and K League 2 teams have been permitted to field their reserve teams in the K4 League.
Clubs
Current clubs
K League 1
K League 2
All-time clubs
As of 2026, there have been a total of 40 member clubs in the history of the K League – those clubs are listed below with their current names :- K League's principle of official statistics is that final club succeeds to predecessor club's history and records.
- Clubs in italics no longer exist.
Champions
Promotion-relegation play-offs
The K League promotion-relegation play-offs were introduced in 2013 and are contested between the eleventh-placed team of K League 1 and the runners-up of K League 2. The first leg is always played at the second division team's home ground, while the second leg is played at the first division team's home ground. Starting in 2022, another series was added between the tenth-placed team of K League 1 and the third-placed team of K League 2.Records and statistics
K League officially includes records of K League 1, K League 2 and Korean League Cup in its statistics.Restriction of foreign players
At the inception of the K League in 1983, only two Brazilian players made rosters. At the time, rules allowed each club to have three foreign players and that the three could also play simultaneously in a game. From the 1996 season, each team had five foreign players among whom three could play in a game at the same time. In 1999, foreign goalkeepers were banned from the league because South Korean clubs excessively employed foreign goalkeepers after watching Valeri Sarychev's performances at that time. In 2001 and 2002, the limit on foreign players was expanded to seven but only three could play in a game at the same time. The limit was lowered to five in 2003, four in 2005, and three in 2007. Since 2009, the number of foreign players went back up to four per team, including a slot for a player from AFC countries. Between 2020 and 2024, Southeast Asian players could be registered under the ASEAN Quota. The prohibition of foreign goalkeepers was abolished in 2025, and they will be able to play in the league since 2026.| Season | Lineup | Squad | Note |
| 1983–1993 | 2 | 2 | |
| 1994 | 2 | 3 | |
| 1995 | 3 | 3 | |
| 1996–2000 | 3 | 5 | The number of foreign goalkeepers' appearances was limited in 1997 and 1998, and their employment was banned in 1999.
|
| 2001–2002 | 3 | 7 | Temporary operation due to frequent call-ups of the World Cup team. |
| 2003–2004 | 3 | 5 | |
| 2005 | 3 | 4 | |
| 2006–2008 | 3 | 3 | |
| 2009–2019 | 3+1 | 3+1 | |
| 2020–2024 | 3+1+1 | 3+1+1 | |
| 2023–2024 | 3+1 | 5+1 | |
| 2025–present | 4 | 5 or 6 | K League 1 teams can register six foreign players each in their squads, while K League 2 teams can register five. The foreign goalkeepers' employment is being allowed since 2026. |
Relocation of clubs
In early years, the hometowns of K League clubs were determined, but they were pointless in substance because the clubs played all K League matches by going around all stadiums together. The current home and away system is being operated since 1987. The clubs were relocated from provinces to cities in 1990, but clubs are currently based in their area regardless of province and city since 1994. In 1996, the decentralization policy was operated. In result 3 clubs based in Seoul were relocated. Since 1996, it is obligatory for all clubs to include hometown name in their club name.| Club | National tour system | Home and away system |
| Pohang Steelers | Daegu–Gyeongbuk | Daegu–Gyeongbuk → Pohang |
| Jeju SK | Seoul–Incheon–Gyeonggi → Seoul | Seoul → Incheon–Gyeonggi → Seoul → Bucheon → Jeju |
| Busan IPark | Busan–Gyeongnam | Busan–Gyeongnam → Busan |
| Ulsan HD | Incheon–Gyeonggi → Incheon–Gyeonggi–Gangwon | Gangwon → Ulsan |
| FC Seoul | Chungnam–Chungbuk | Chungnam–Chungbuk → Seoul → Anyang → Seoul |
| Seongnam FC | — | Seoul → Cheonan → Seongnam |
| Gimcheon Sangmu | — | Gwangju → Sangju → Gimcheon |
| Asan Mugunghwa | — | Unlocated → Ansan → Asan |