The 2025 Copa Sudamericana will be contested by 56 clubs from ten South American countries. The first phase will have 32 clubs from eight associations, except Argentina and Brazil, which play against teams from the same country in a single game. The 16 classified join 6 from Argentina, 6 from Brazil and 4 teams eliminated from the 3rd phase of the Libertadores in the Group Stage. The group leaders go straight to the Round of 16. Before that, there will be the Round of 16 Playoffs, between the second-placed teams in each group and the third-placed teams in the Libertadores group stage. The eight winners of these games face the top teams in the South American groups in the Round of 16. In case of equal scores in the Group Stage, the tiebreaker criteria are:

1) better goal difference;
2) more pro goals;
3) more goals as a visitor;
4) Conmebol ranking.

From the Round of 16 Playoffs to the Semifinal, the clashes are knockout, in round-trip games and, in case of equality in points, the tiebreaker criteria are:

1) better goal difference;
2) penalty shootout.

Final is played in a single game. In the event of a tie, there is a 30-minute extra time and, if equality persists, there is a penalty shootout.