Departing on 19 February for her third patrol, she headed through Lombok Strait to the Java Sea. After sighting the heavy cruiser and two escorts heading for Sunda Strait following the Allied defeat in the Battle of the Java Sea, "Sailfish" intercepted an enemy destroyer on 2 March. Following an unsuccessful attack, she was forced to dive deep to escape the ensuing depth charge attack from the destroyer and patrol aircraft. That night, near the mouth of Lombok Strait, she spotted what appeared to be the aircraft carrier , escorted by four destroyers. "Sailfish" fired four torpedoes, scoring two hits. Leaving the target aflame and dead in the water, "Sailfish" dove, the escorts delivering forty depth charges in the next 90 minutes. She eluded destroyers and aircraft and arrived at Fremantle, Western Australia, on 19 March, to great fanfare, believed to be the first U.S. sub to have sunk an enemy carrier. In reality, the "Kaga" was scuttled in June, 1942, after damage sustained during the Battle of Midway, in that vicinity. Postwar, it was revealed "Kaga" had been nowhere in the area of Lombok Strait, and the target had in fact been the aircraft ferry "Kamogawa Maru", still a valuable target.