Clubs must register a 'List A' and 'List B' squad for European competitions. List A has a maximum of 25 players, with a minimum of eight 'locally trained' members, of which no more than four can be 'association-trained'. If a club submits fewer locally-trained players, their squad maximum is reduced proportionally. At least two goalkeepers must be in List A, and three total across both lists.

List B has no upper limit and must be submitted by 23:59 CET the day before a match. Players are eligible if born on or after 1 January 2005, have been with the club for two consecutive years since their 15th birthday, or three consecutive years including a loan spell. Players aged 16 can qualify if registered for the previous two years uninterrupted.

After the September deadline, List A is locked for the league phase. Clubs reaching the knockout stages can register up to three new players by 4 February 2027. Players who changed clubs in January can play from the knockout rounds, with the 25-player limit and locally-trained minimum still applying.

In exceptional injury or illness cases, a player sidelined for at least 60 days can be temporarily replaced by a player registered before the List A deadline. The locally-trained quota stays the same, and the affected player cannot return to the competition.