For the league phase of the 2026/27 Champions League, the central rule is simple: being under contract and registered in the domestic championship is not enough. The player must also be registered with UEFA under the competition rules. List A must be submitted by 2 September 2026 at 23:59 CET. List B remains open throughout the season, but it can only include players who meet the specific age and club-training criteria.
That distinction explains much of the confusion at the end of a transfer window. A transfer may be valid domestically and still be completed too late for the Champions League league phase. UEFA itself notes that domestic transfer windows vary among national associations, while the European List A deadline is the same. To play, the player must be properly registered with the national association and also meet UEFA registration requirements.
The List A deadline for the league phase
The 2026/27 Champions League regulations set 2 September 2026 at 23:59 CET as the List A deadline for matches from the first league-phase matchday onward. In practical terms, this is the cut-off that matters to clubs already qualified for that stage.
Clubs that came through the play-offs are not locked into the list used in the previous round. UEFA clarifies that clubs qualifying through the play-offs may submit their own list for the league phase. Therefore, a change made between the play-off and the 2 September deadline can be incorporated normally, provided the player also meets the other eligibility conditions.
The important point is that the domestic transfer-window deadline and the List A deadline run on different clocks. If a domestic window still allows a transfer after 2 September, the deal may be valid under national rules, but the new signing cannot be added to the league-phase List A merely because the player was registered domestically after that cut-off.
List A: 25 players, but not every slot is unrestricted
List A can contain a maximum of 25 players during the season and must include at least two goalkeepers. The number 25, however, does not mean a club has 25 completely unrestricted places for its European squad.
The regulations reserve at least eight places for locally trained players. Within that group, no more than four may be classified as association-trained players. The remaining reserved places must be filled by club-trained players if the team is to use the full capacity of List A.
For UEFA, a club-trained player is one who, between the ages of 15 and 21, was registered with the current club for three complete seasons or 36 months. An association-trained player follows the same period requirement but may have been registered with the current club or with other clubs affiliated with the same national association.
The practical consequence is often overlooked: if a club does not have eight locally trained players, its List A limit decreases. A team with only seven players who meet that requirement does not receive an extra place for a player from another category; its maximum becomes 24 names. With six, the ceiling falls to 23, and so on.
List B is not a second List A
List B is different because it has no numerical limit on players during the season. It can be updated and submitted by 23:59 CET on the day before the match in question. This provides flexibility to use young players who are already part of the club structure.
That flexibility, however, comes with clearly defined criteria. For 2026/27, the player must have been born on or after 1 January 2005 and, from the age of 15, must have accumulated the required training link with the club. The rule accepts either an uninterrupted period of two years or three consecutive years with no more than one loan of up to one year to another club in the same association. For 16-year-old players, there is a specific condition requiring uninterrupted registration during the previous two years.
For that reason, List B does not work as a shortcut to register any young signing acquired after the List A deadline. A name can only be added if the player meets the specific List B requirements. A player who has just arrived from another club will normally not satisfy that training history simply because of being young.
In addition, UEFA requires at least three goalkeepers across Lists A and B combined, although only two of them must be on List A.
What happens to a signing completed at the last minute
If a signing is registered by the club and placed on List A by 2 September, the player can be eligible for the league phase, provided the general UEFA and national-association rules are also met. If the deal is completed after the deadline, the situation changes.
UEFA's official guidance for 2026/27 is direct: transfers completed after the List A deadline are not eligible for the league phase. This remains true even when the country's domestic transfer window is still open. The contract and domestic registration authorize the player to take part in
competitions for which the player is otherwise properly registered, but they do not reopen the European list.
There is also an important distinction for a player who changed clubs after appearing in qualifying rounds. A player who has appeared in Champions League, Europa League or Conference League qualifying or play-offs for one team may represent another club from the league phase onward, provided the player is properly registered for the new club. The old idea that any European appearance automatically makes a player ineligible to represent another team in the same season does not describe the current rule.
Can List B save a player left out on 2 September?
It can, but only when the player genuinely qualifies for List B. This is the typical case for young players developed within the club structure who do not need to occupy a List A place and can be added before each match.
It is not correct, however, to treat List B as a parallel transfer window. The fact that it can be updated until the day before a match does not remove the age and training requirements. For an external signing completed after 2 September, entering the league phase through List B is, as a rule, incompatible with the very requirement for a prior training relationship with the club.
Does an injury open a place for any new signing?
No. The exception for outfield players is narrow and was designed for cases of long-term injury or illness, not to freely reopen the European market.
During the league phase, up to and including matchday six, a club may temporarily replace no more than one List A outfield player when an injury or illness is expected to last at least 60 days. The replacement must have been registered with the club, under the general eligibility rules, before the 2 September List A deadline. If the sidelined player occupied a club-trained or association-trained place, the required composition of those slots must also continue to be respected.
This creates an important consequence for a last-minute signing: an injury occurring after the deadline does not simply allow a club to sign someone after 2 September and place that player in the injured player's slot. For this outfield-player exception, the replacement already had to be registered with the club before List A closed.
When the injured player recovers, that player becomes eligible again and the temporary replacement must leave the list. Even if the recovery occurs before 60 days have elapsed, the replaced player remains unable to play in UEFA club competitions until the end of that minimum period.
The goalkeeper exceptions are different
The regulations treat goalkeepers separately. In the event of an injury or illness considered long-term, lasting at least 30 days, a club may temporarily replace the goalkeeper and register a new name at any time during the season, always subject to the general eligibility conditions. The replacement goalkeeper does not have to be locally trained, even if the player removed from the list had that status.
There is another specific case: if a goalkeeper leaves on a permanent transfer after matchday six and before the end of the league phase, the club may replace that goalkeeper on List A. If the team advances to the knockout phase, the goalkeeper added during the league phase will count toward the quota of new registrations allowed for the knockout stage.
These rules show why it is unsafe to reduce all exceptions to a sentence such as "an injury allows a player change." The minimum period, the position, the point in the season and the replacement player's registration history all change the answer.
The new deadline before the knockout phase
After the league phase ends, qualified clubs receive a new opportunity to change List A. The general rule allows up to three new eligible players to be registered by 4 February 2027 at 23:59 CET.
These new players may even have appeared for another club in Champions League, Europa League or Conference League qualifying, play-offs or the league phase. Even so, the 25-player List A limit remains in force, as does the reservation of places for locally trained players. If adding the new names takes the list above 25, other players must be removed.
The regulations provide an additional exception for clubs from domestic championships that begin and end within the same calendar year, in specific situations involving the departure of many players after the league phase. That possibility can increase the quota by one or two registrations, but it is not a general rule for every participant.
How to interpret a signing announcement close to the deadline
When a club announces a signing close to 2 September, the correct question is not only whether the transfer was completed. Three separate checks are needed.
First, the player must be properly registered with the national association under local and FIFA rules. Second, for the league phase, the player must be included on List A by the deadline or genuinely qualify under the List B conditions. Third, if the deadline has already passed, any possibility of later registration depends on the specific exceptions in the regulations, not simply on the existence of an open squad place.
This reading avoids two common mistakes. The first is concluding that "the transfer window is still open, so the player can play in the Champions League." The second is assuming that "List B stays open, so any young player can be added." In 2026/27, neither conclusion is sufficient on its own.
What applies to the 2026/27 Champions League
For the league phase, 2 September 2026 at 23:59 CET is the main List A cut-off. The limit is 25 players, with eight places reserved for locally trained players and no more than four of those eight occupied by players trained only within the association. List B can be updated until the day before each match, but it is intended for young players who meet the club-training requirements.
A signing completed after the deadline does not gain European eligibility simply because the domestic transfer window remains open. The routes available after the deadline are specific: List B for players who genuinely meet its criteria, injury or illness replacements under the conditions in
the regulations, separate goalkeeper rules and the new window for up to three registrations before the knockout phase.
If there is doubt about a specific player, the decisive point is to verify that player's status on the UEFA lists and the eligibility rules applicable at that stage of the competition. The official regulations in Articles 30, 31 and 32 are the reference that prevails over summaries and transfer announcements.
