Challengers League clubs

Buyeo Football Club (Korean: 부여 FC) was a South Korean football club based in the county of Buyeo. The club was a member of the K3 League, an semi-professional league and the fourth tier of league football in South Korea, since the 2016 season.

Ulsan Citizen Football Club (Korean: 울산 시민 축구단) is a South Korean football club based in the city of Ulsan. The club plays in the K3 League, the third tier of football in South Korea. Following the club's foundation in 2018, it joined the K3 League Basic in the 2019 season, and was promoted to the rebranded K3 League in 2020 after finishing as runners-up in the inaugural season of the K4 League.

Busan Football Club (Korean: 부산 FC) was a South Korean football club based in Busan. The club was a member of the K3 League Basic, an semi-professional league football in South Korea, from the 2017 season to 2018 season.

Icheon Citizen Football Club (Korean: 이천 시민 축구단) was a South Korean football club based in Icheon City and former member of the K4 League, a semi-professional league and the fourth tier of football in South Korea. The club was founded in 2009 when disbandment in 2020.

Chuncheon Citizen Football Club (Korean: 춘천 시민 축구단) is a South Korean football club based in Chuncheon, Gangwon. The club plays in the K3 League, the third tier of South Korean football. Chuncheon FC's home ground is Chuncheon Songam Sports Town.

Seoul Pabal Football Club (Korean: 서울 파발 FC) was a South Korean soccer club based in Eunpyeong-gu, Seoul. It was a member of the K3 League, an amateur league and the third tier of league football in South Korea.

Gyeongju Citizen Football Club (Korean: 경주 시민 축구단) was a South Korean football club based in the city of Gyeongju. It is a former member of the K3 League, the third tier of league football in South Korea until 2020 season.

Cheonan City FC (천안 시티 FC) is a South Korean football club based in Cheonan that competes in the K League 2, the second tier of South Korean football. They play their home games at the 26,000 capacity Cheonan Stadium.

Bucheon Football Club 1995 (Korean: 부천FC 1995) is a South Korean professional football club based in Bucheon that competes in the K League 2, the second tier of South Korean football. The club was founded in 2007 by a group of former Bucheon SK supporters after its move to Jeju in early 2006.

Seoul Nowon United Football Club (Korean: 서울 노원 유나이티드 FC) (formerly known as Seoul United FC) is a South Korean semi-professional football club based in Nowon District, Seoul. It currently competes in the fourth tier of the South Korean football league system, the K4 League. Until 2018, the club was named Seoul United FC.