During the duration of the tournament, participating clubs were not required to release players to their national teams for tournaments in the
FIFA calendar (namely the
2025 CONCACAF Gold Cup). However, clubs were still required to release players for the international window immediately prior to the tournament, from June 2 to 10, 2025. In order to be eligible, all players in each squad had to be duly registered with their club in accordance with the both regulations of FIFA and the relevant member association. The potential impact of transfers on the tournament was questioned, as the
transfer window was open in many leagues during the tournament, and thus players in the tournament could potentially be moved to a different club during the tournament, including to other participating clubs. In addition, many player contracts in Europe expired on June 30, which could have affected the participation of some players. In view of this, in October 2024 the
FIFA Council finalized the rules on transfers for the tournament, with the intent to "equalise inconsistencies created by differences in registration periods and domestic-season timings between participating clubs to the greatest extent possible". Therefore, all member associations of participating clubs were given the option of opening an extraordinary registration window from June 1 to 10, 2025, which applied to all clubs of the relevant member association. This allowed for clubs to register new signings prior to the start of the competition, instead of being limited by the usual transfer window dates, often which opened on July 1. While opening the additional window remained at the full discretion of the member associations, all twenty associations with participating clubs did so. Additionally, as the transfer window for many FIFA member associations opened during the course of the tournament, clubs could make changes to the final list between June 27 to July 3, 2025, subject to the following conditions: • Clubs could replace players whose contracts expired during the tournament. • Clubs could register up to two additional players to their final list, not counting towards the 35-player limit. • No more than six players in total could be added. • Any player added had to be registered for their club with the relevant member association during that association's standard registration window. • Any player added was only eligible to play in the next match if FIFA was notified at least 48 hours before kick-off. However, for players and coaches with a contract ending or transfer planned during the tournament, FIFA's objective was to "encourage clubs and players whose contracts are expiring to find an appropriate solution to facilitate the players' participation". While players typically could only be registered with up to three clubs during a single season, and be eligible to play official matches for two clubs within this period, matches at the Club World Cup did not count towards this restriction. Should two clubs have included the same player on their respective provisional lists, the FIFA general secretariat would have decided which club the player would represent after hearing all concerned parties. While clubs could make changes to their final list during the competition, no player could represent multiple clubs during the tournament. ==Group A==