The USS Bluefin was placed on Atlantic Patrol and was assigned to Submarine Squadron 55 (SubRon 55). On 15 October 1942, she was sent on her first war patrol under the command of Captain James Deerborn in support of Operation Flame. Her first war patrol lasted from 28 November to 27 December 1942 off the Spanish coast in the Bay of Biscay. From 19 May 1943 to 14 August 1943 the USS Bluefin would go on seven more war patrols before having to return to the United States to take on her final mission.