While patrolling near the entrance to Daito Wan on the western coast of Korea on 18 April, she sank one small freighter with gunfire and damaged another. Off the China coast on 22 April, "Trutta" narrowly escaped damage when an enemy float plane dropped two bombs which exploded over the diving submarine. Shortly after midnight three days later, as "Trutta" patrolled west of Quelpart Island, lookouts on the submarine's bridge were startled to see a torpedo pass astern. As "Trutta" put on speed and turned parallel to the torpedo's wake, another torpedo passed by her port side moving from stern to bow, a sinister reminder that she was not alone in the Yellow Sea. Fortunately, "Trutta" observed no further sign of the Japanese submarine, and she continued her patrols until 26 April when she headed for Guam.