In which Star Trek film does Sulu command the USS Excelsior?

Hikaru Sulu commands the USS Excelsior in Star Trek VI: The Undiscovered Country.

By the time of the film’s 2293 setting, Sulu has left the original USS Enterprise and become captain of the Excelsior, a newer Federation starship. During the opening events, the Excelsior detects the destruction of the Klingon moon Praxis, an accident that destabilizes the Klingon Empire and creates the political crisis at the center of the story.

Sulu’s command is significant because it shows the original Enterprise crew moving into senior Starfleet roles. While Captain James T. Kirk and his crew escort Klingon Chancellor Gorkon to peace negotiations, Sulu and the Excelsior investigate the Praxis disaster and later assist in the unfolding crisis. George Takei reprises the role and receives a larger command role than in most earlier films.

The mix-up usually comes from the timing of Sulu’s promotion. He does not command the Excelsior in Star Trek III, Star Trek IV, or Star Trek V. Star Trek VI is the film that explicitly presents him as its captain, while later television stories also revisit his service aboard the ship.