Ahead of the 2026 K League season opener, we summarized the major rule and operational changes for the new season.
■ 'Gimhae, Yongin, Paju' join K League 2, K League operates with 29 clubs
Gimhae FC2008, Yongin FC and Paju Frontier FC will participate in K League 2. Accordingly, the K League will operate with 12 first-division teams (K League 1) and 17 second-division teams (K League 2), a total of 29 clubs. K League 2 will have 17 teams each playing 32 matches, for a total of 272 matches.
■ foreign player roster limit abolished, foreign goalkeeper registration allowed
The limit on the number of foreign players a club can hold has been abolished, allowing clubs to register foreign players without a cap. However, matchday squad registration and participation are limited to five in K League 1 and four in K League 2. In addition, the rule prohibiting registration of foreign goalkeepers has been abolished, allowing foreign goalkeepers to return to the K League after about 27 years.
■ K League 2 matchday squad expanded to 20 players
K League 2's matchday squad will be expanded from the previous 18 to up to 20 players. This measure is intended to increase the variety of substitute usage to raise performance and to guarantee playing opportunities for domestic players in response to the expanded registration of foreign players. K League 1 has operated with a 20-player matchday squad since the 2024 season.
■ relaxation of the U22 mandatory playing rule
The mandatory playing rule for K League players aged 22 and under will also be relaxed. In K League 1, regardless of whether U22 players play, five substitutions can be made during a match. However, the rule that requires at least two U22 players to be included in the matchday squad (20-player entry) remains in place. If only one U22 player is included, the squad is limited to 19; if none are included, it is limited to 18.
K League 2 will have its mandatory playing rule relaxed following the existing K League 1 model. ▲ If a U22 player does not play, three substitutions are allowed; ▲ if one U22 player starts and there is no additional substitute appearance, four substitutions are allowed; ▲ if a U22 player does not start but two or more U22 players appear as substitutes, four substitutions are allowed; ▲ if two or more U22 players start, or one U22 player starts and one or more U22 players appear as substitutes, five substitutions are allowed.
■ change in K League promotion and relegation format..up to four teams can be promoted
With the Gimcheon Sangmu residency agreement expiring at the end of the 2026 season and the number of K League 1 teams expanding to 14 from the 2027 season, the promotion and relegation format for the 2026 season has been changed.
The promotion and relegation format varies depending on Gimcheon Sangmu's K League 1 ranking. If Gimcheon Sangmu finishes last in K League 1, only Gimcheon Sangmu will be relegated and there will be no additional relegated teams. In K League 2, the teams finishing first and second are automatically promoted, and teams placed third through sixth go through a four-team playoff, with the final winner being promoted. In that case, the promotion-relegation playoff will not be held.
If Gimcheon Sangmu does not finish last in K League 1, Gimcheon Sangmu will be relegated and the K League 1 last-place team will participate in the promotion-relegation playoff. In K League 2, the teams finishing first and second are automatically promoted, and teams placed third through sixth go through a four-team playoff, with the final winner being promoted. The team that loses in that promotion decider will play a promotion-relegation playoff against the K League 1 last-place team.
■ other changes
▶ All K League clubs will be required to have a technical director. The technical director is responsible for establishing the club's unique football identity and implementing long-term technical development plans, overseeing the club's technical development and squad operations.
▶ The player standard contract's 'clause allowing a player to terminate the contract if the club defaults on wages' has been revised. Previously, if a club failed to pay annual wages for three months or more without justifiable reason, the player could immediately terminate the contract; after the revision, if annual wages are unpaid for two months or more, the player must notify the club of the debt and give the club 15 days to remedy the situation. This revision reflects FIFA RSTP (Regulations on the Status and Transfer of Players), and if the club does not correct the situation after 15 days, the player may terminate the contract.
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