The 2025 K League 1, also known as the Hana Bank K League 1 for sponsorship reasons, was the 43rd season of the top division of professional football in South Korea, and the twelfth season of the K League 1. Ulsan HD were the three-time defending champions.
The following rules were newly introduced for the 2025 season.
FC Anyang were promoted from the K League 2 for the first time in the club's history. Incheon United were relegated to the K League 2, absenting from the top flight of South Korean football for the first time in the club's history.
The following twelve clubs are competing in the 2025 K League 1.
Each team may have up to six foreign players registered, but may only field up to five at any given time. As a military-owned team, Gimcheon Sangmu are not allowed to sign any foreign players.
A North Korean player is considered to be a domestic player under South Korean nationality law. As of 2025, K League has a homegrown system under which players of foreign nationality who have grown up in Korea are considered to be domestic players when registering as new players.
Players in bold were registered during the mid-season transfer window.
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Teams played each other twice, once at home, once away.
Teams played each other once, either at home or away.
Teams played each other once, either at home or away.
The tenth-placed team and the eleventh-placed team played the play-off winners and the runners-up of the K League 2, respectively, in the relegation play-offs.
The first leg between Suwon FC and Bucheon FC 1995 was postponed from 4 December to 5 December due to heavy snow.
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Jeju SK won 3âÂÂ0 on aggregate and therefore both clubs remain in their respective leagues.
Bucheon FC 1995 won 4âÂÂ2 on aggregate and was promoted to K League 1, while Suwon FC was relegated to K League 2.
The 2025 K League Awards was held on 1 December 2025.