The UEFA Nations League was expanded to include a new knockout round taking place in March 2025, thereby creating continuity between the group phase ending in November and the finals played in June.

The League A group winners and runners-up participated in home-and-away quarter-finals, with the winners of these ties qualifying for the finals.

The fourth-placed teams in Leagues A and B were automatically relegated to League B and C respectively. The two lowest-ranked fourth-placed teams in League C, meanwhile, were relegated to League D.

The four group winners in Leagues B and C, as well as the two group winners in League D, were automatically promoted to Leagues A, B and C respectively.

The third-ranked teams of League A and the runners-up of League B, as well as the third-ranked teams of League B and the runners-up of League C, played home-and-away promotion/relegation play-offs.

There will also be play-offs between the two best-ranked fourth-placed teams from League C and the two runners-up from League D.

The expansion of the UEFA Nations League into the International Match Calendar window of March concerned only a select number of teams with the remaining teams starting the European Qualifiers for the 2026 FIFA World Cup.

The 12 group runners-up from the European Qualifiers will participate in the play-offs for the World Cup finals along with the four best-ranked group winners of the 2024/25 UEFA Nations League that did not finish their European Qualifiers group stage in first or second place.

The 16 teams who enter the play-offs will be drawn into four play-off paths, with four teams in each. Play-off matches will be played in single-leg semi-finals followed by single-leg finals within the same international window in March 2026.

The UEFA Nations League was devised to minimise meaningless friendlies and give nations competitive encounters with equally ranked teams.

Teams from all the European associations compete in a league structure featuring promotion and relegation. In the first edition of the tournament, they were divided into 12 teams in League A, 12 in League B, 14 in League C and 16 in League D.