Following outfitting and shakedown, "Trutta" underwent 30 days of intensive training in the Portsmouth-New London area and then set a course southward and steamed via the Canal Zone to arrive at Pearl Harbor on 25 February 1945. After a period of advanced training, "Trutta" got underway from Oahu with and , members of a coordinated attack group under "Trutta"'s direction and arrived at Saipan on 30 March. The following day, as she was leaving Tanapag Harbor on her first war patrol, the submarine struck a cable connected to an oil drum adrift in the charted channel and was forced to return to Saipan to repair her damaged propeller blades. The submarine finally got underway on 3 April and proceeded as rapidly as possible toward her patrol area.