All participating clubs play
home and away season in the K4 League. The promotion and relegation system exists between the
K3 League and the K4 League, but does not exist between the K4 League and the amateur K5 League, although there are plans to impement it by 2027. For the 2025 season, the winner of the league will be crowned champions without a playoff and gain automatic promotion. The 2nd-placed team may gain promotion via a two-game playoff series against the 14th-place team in the
2025 K3 League. Also for the 2025 season, and following the example of K League, match day squad lists have increased from 18 to 20 players. At least three players must be Korean nationals, aged 23 or younger, and at least one of the three must be in the starting eleven. The Asian player quota has been removed, and teams may now include 4 foreign players of any nationality. K4 League teams are allowed to recruit professional players who choose to do social service instead of military service. ==Clubs==