Major League Soccer has confirmed that all 27 of its United States-based clubs will return to the U.S. Open Cup in 2027, restoring full league participation to the country’s oldest domestic knockout competition for the first time since 2023.

The move marks a notable shift after a period in which not every MLS club took part. In the 2026 edition of the tournament, only 16 U.S.-based MLS teams were involved, leaving the competition without full representation from the top domestic league. By contrast, the league’s announcement means the 2027 field will again include every eligible U.S.-based MLS side.

MLS said the change comes alongside the lifting of its rule that had capped clubs at two non-league competitions. That adjustment will allow qualified teams to compete in the U.S. Open Cup, Leagues Cup and Concacaf Champions Cup in the same season as league play. The development is significant because it places the Open Cup back into the broader competition calendar for MLS clubs, rather than leaving participation limited to a partial group.

The league also said clubs will enter the tournament in the round of 64, with the opening matches set to begin in July of 2027. That timing is intended to align with the start of the new summer-to-spring MLS competition schedule for the 2027-28 regular season. MLS clubs will also receive hosting priority for their opening match, giving them the first opportunity to stage early-round games at home.

In a statement carried in the league’s news release, MLS executive vice president of sporting and matchday Nelson Rodriguez described the Lamar Hunt U.S. Open Cup as a competition that connects leagues, clubs and fans in a distinctive way. He also framed the tournament as a chance for MLS clubs to build a memorable chapter in its history and, for successful teams, earn qualification to the Concacaf Champions Cup.

The format details extend beyond the first round. A live draw will follow the round of 64 to determine the round-of-32 and round-of-16 matchups and hosting rights. MLS also said the 2027 Open Cup will tweak roster rules, expanding gameday squads from 18 players to 20. According to the league, clubs may choose from contracted first-team players as well as MLS NEXT Pro and academy players, a structure meant to give younger players competitive minutes while helping clubs manage overlapping competitions.

The schedule for the latter stages is already mapped out. The round of 32 is scheduled for September 14 and 15, while the round-of-16 dates will be announced later. The competition will then resume for the quarterfinals on November 23 and 24, with semifinals on December 1 and the final on December 15.

The announcement comes while the 2026 U.S. Open Cup is still being played. Four MLS teams remain in the semifinals, which are set for September 16. Columbus Crew, the 2002 tournament champion, will host Orlando City SC, the 2022 champion, in one semifinal. In the other, the Colorado Rapids will host St. Louis City. The winner of the Columbus-Orlando semifinal will host the final on October 21.

For the Open Cup, the 2027 entry list represents a return to full-strength MLS participation after a reduced field in 2026. For clubs, it also restores a direct route into a competition that links league seasons, domestic cup play and continental qualification in a single calendar.