The transfer window may decide which players a club owns, but UEFA registration rules decide which of them can actually appear in the Champions League.
Ahead of the 2026/27 league phase, clubs must organise eligible players into two groups: List A and List B. The distinction is more than paperwork. It influences transfer decisions, rewards academy development and can leave an expensive signing outside the European squad.
What is UEFA List A?
List A is the main competition squad. It can contain up to 25 players, but that maximum depends on the club meeting UEFA's locally trained player requirements.
Eight places are reserved for locally trained players. Within that group, no more than four can be association-trained rather than club-trained. A club-trained player has spent the required development period registered with the current club, while an association-trained player developed at another club in the same national association.
The rule does not force a club to name eight locally trained players. Instead, an unfilled locally trained place reduces the permitted size of List A. A team with only seven eligible locally trained players can therefore register no more than 24 players on List A.
What is UEFA List B?
List B is designed for younger players who have a meaningful development history with their club. It is not simply a list for anyone under 21.
For the 2026/27 Champions League, the precise birth-date threshold is set by the competition regulations, and the player must also satisfy a club-registration period after turning 15. UEFA permits eligible List B players to be added during the season, subject to the submission deadline before a match.
That flexibility allows clubs to use academy players without occupying one of the limited List A spaces. It also explains why two players of the same age can be treated differently: a long-serving academy graduate may qualify for List B, while a newly signed young player may need a List A place.
Why a new young signing may not qualify
Age is only one part of the test. A 19-year-old bought in the summer may be young enough but lack the required period of registration with the new club.
This is one of the most common sources of confusion after transfer deadline day. Supporters see a player described as an under-21 signing and assume he can be placed on List B. UEFA's development-history requirement means that assumption can be wrong.
How the homegrown quota changes squad planning
The locally trained rule places a practical value on academy graduates and long-serving domestic players. Clubs cannot always replace several homegrown players with overseas signings and still retain a full 25-player European squad.
Sporting directors therefore have to consider at least three questions before completing a deal:
- Does the player need a List A place?
- How many locally trained slots can the club fill?
- Which positions would be left short if the maximum squad size is reduced?
The answer can affect whether a fringe player is sold, loaned or kept until the registration deadline.
Can squads change after the league phase?
UEFA competitions permit limited changes before the knockout phase, subject to the regulations and deadlines for that season. Clubs cannot simply rewrite the entire squad after the winter transfer window.
That makes the first List A decision important. A club has to balance immediate fitness concerns against the need for cover across a long league-phase schedule.
Why a player can play domestically but not in Europe
Domestic leagues and UEFA competitions operate separate registration systems. A player may be eligible for league matches but omitted from the Champions League list because of space, locally trained requirements or a deadline.
Omission does not necessarily mean a dispute or an imminent transfer. It can be a mathematical consequence of the squad rules.
The simple version
- List A is the limited senior squad and includes locally trained requirements.
- List B is for qualifying young, club-developed players and can be updated more flexibly.
- Being under 21 does not automatically make a player eligible for List B.
- Missing locally trained players can reduce the size of List A.
- Domestic eligibility does not guarantee Champions League eligibility.
See our guide to the Champions League league-phase format and follow the Football section for fixtures and competition updates.
