The South Korean football league system contains two professional leagues, two semi-professional leagues, and various amateur leagues for Korean football clubs.
The highest level of football in South Korea is the K League 1, which was founded in 1983. K League 2 was founded in 2013 and is currently a second division. Below the level of the professional leagues are the semi-professional K3 League, which was founded in 2007 and refounded in 2020, and the K4 League, which was founded in 2020, and serve as the third division and fourth division, respectively.
There was no avenue for progression between any of the leagues until 2012, when the K League 2 was founded.
Korean National Semi-Professional Football League was a semi-professional football league between corporate teams in South Korea from 1964 to 2002. In 1983, with the establishment of K League which is a professional league, Semi-professional League became the second tier and remained until 2002 before Korea National League was officially founded in 2003. The third tier K3 League was founded as an amateur league in 2007, and became the fourth tier after K League 2, the second division of the professional league, was founded in 2013. K3 League also divided into the Advanced and the Basic, and they became semi-professional leagues with new names, K3 League (semi-professional) and K4 League, after the merger of National League in 2020. South Korean leagues are using systems of promotion and relegation in each of three classes: professional, semi-professional and amateur; but there are still no promotion and relegation between classes.
|Professional leagues (K League)|
|Year||Tier 1||Tier 2||Tier 3||Tier 4||Tier 5||Tier 6||Tier 7||Tier 8 and under|
|1983||K League||Korean League Division 1||Korean League Division 2|
|1984–2002||K League||Semi-professional League|
|2003–2006||K League||National League|
|2007–2012||K League||National League||K3 League (amateur)|
|2013–2016||K League 1||K League 2||National League||K3 League (amateur)|
|2017–2019||K League 1||K League 2||National League||K3 League Advanced||K3 League Basic||Under construction|
|2020–present||K League 1||K League 2||K3 League||K4 League||K5 League||K6 League||K7 League||Regional competitions|
Outside this league structure, there are university, reserve and youth level competitions. University clubs' U-League and reserve teams' R League are operating independently from the league system. Promotion and relegation between K League 2 to K3 League start from 2023 season.
|Level||League / Division||Difficulty|
|1||K League 1
↓ 1 relegation spot + 2 relegation playoff spot
|2||K League 2|
↑ 1 promotion spot + 2 promotion playoff spot
No relegation (relegation spot start from 2023 season)
No promotion (promotion spot start from 2023 season)
↓ 2 relegation spots + 1 relegation playoff spot
↑ 2 promotion spots + 1 promotion playoff spot
66 clubs / 11 regions
↓ 11 relegation spot
199 clubs / 31 regions
↑ 11 promotion spot
↓ 30 relegation spot
1127 clubs / 178 regions
↑ 30 promotion spot
↓ relegation spot
↑ promotion spot
All K League, K3 League and K4 League sides qualify for the Korean FA Cup tournament. The top eleven sides from the K5 League gained qualification to the 2020 season's FA Cup tournament. The Korean League Cup competition was open to K League teams only, whilst sides from the National League could compete in the National League Championship, but both were abolished.[when?]
At present, four South Korean sides qualify automatically for the AFC Champions League. Three top teams from K League 1 automatically gains entry to the AFC Champions League. The Korean FA Cup winners also qualify for the AFC Champions League only. However, if the champions of Korean FA Cup are not members of K League, the fourth placed team of the K League 1 receive the entry spot.