CONCACAF Nations League continued to be played in the format introduced for
2023–24 season. League A featured sixteen teams. The four best-ranked teams according to the
CONCACAF Ranking Index received a
bye to the quarter-finals. The remaining twelve teams entered the group stage using a
Swiss-system tournament format. The teams were divided into two groups of six teams, with each team playing four matches against group opponents (two at home and two away). The top two teams from both groups advanced to the quarter-finals and were joined by the four teams which received a bye. The teams advancing from the group stage were drawn into ties against teams that received a bye, which were played on a
two-legged home-and-away basis. The four quarter-final winners advanced to the Nations League Finals, which were played in a knockout format, consisting of the semi-finals, third place play-off, and final match to determine the champions. League B featured sixteen teams divided into four groups of four. Each team played six matches in a double
round-robin format. Unlike previous editions, matches were not played in standard home-and-away format. Instead, for each FIFA Match Window, matches in each group were played at a centralized venue. The third-best-ranked teams in each group hosted all four September matches (matchday 1 and 2), the second-best-ranked teams hosted all four October matches (matchday 3 and 4), and the best-ranked teams hosted all four November matches (matchday 5 and 6). If a team was unable to host matches, CONCACAF reserved the right to select a venue. League C featured nine teams. Teams were divided into three groups of three teams, with each team playing four matches in a double round-robin format. Similar to League B, matches in each group were played at a centralized venue. The second-highest-ranked teams in each group hosted the September matches (matchday 1, 2 and 3), and the highest-ranked teams hosted the October matches (matchday 4, 5 and 6). League C was not played at the November window.
Promotion and relegation continued for the 2024–25 season, with the fifth and sixth-placed teams in League A and the fourth-placed teams in League B relegated for the next season. The group winners of Leagues B and C were promoted, as were the best second-placed team of League C. ==Entrants==