In October 1941, SubDivs 15 and 16 were transferred from Pearl Harbor to Manila, increasing the Asiatic Fleet strength to 29 submarines.

Her victim was apparently sinking when the submarine left the scene of the attack, but postwar analysis of Japanese records did not confirm the kill.

She dived and went deep but was severely jolted by four depth charges that knocked out her bow planes, rudder angle indicator, and port annunciator.

His warning that Japanese planes had been over the island during each of the past four days caused the crew a bit of uneasiness until flood tide.

Her next mission, which took her north of Oahu for defense during the Battle of Midway, lasted only ten days, from 30 May to 9 June; but the submarine contacted no enemy shipping.

On 22 October, Tarpon stood out of Pearl Harbor to begin her fifth war patrol which took her to waters north of Bougainville.

Tarpon then returned to Pearl Harbor for a refit and began her next patrol from there on 10 January 1943, with Tom Wogan in command.

At 21:30 on 1 February, approximately 27 miles (43 km) south of Mikura-jima, the submarine fired four torpedoes at a ship and scored one hit.

[11] Her seventh patrol, conducted from 29 March to 15 May, produced no ship contacts; but Tarpon did bombard the radio station at Taroa with her deck gun until return fire from Japanese batteries ashore prompted her to withdraw from the area.

On 16 August, she sighted a Japanese task force which reportedly included an aircraft carrier of the Otaka-class (there was, in fact, no such class; intelligence had misidentified Taiyo), but its high speed prohibited an attack.

On the night of 16 October, she was patrolling the approaches to Yokohama when she sighted a ship which she tentatively identified as a large auxiliary.

Postwar examination of enemy records revealed that the victim was the German raider Michel (Schiff 28) which had been preying on Allied shipping in both the Atlantic and the Pacific.

On the morning of 23 October, the submarine made radar contact on two ships and fired five torpedoes at the larger target.

Tarpon's next war patrol, a photo reconnaissance of various atolls in the Marshall Islands group from 4 December 1943 to 12 January 1944, was largely uneventful.

Tarpon's final war patrol, from 31 August to 14 October, consisted of lifeguard duty in the Truk area.

She served as a training submarine in the 8th Naval District until placed out of service and stricken from the Navy list on 5 September 1956.

Tarpon foundered in deep water, south of Cape Hatteras, North Carolina, on 26 August 1957, while under tow to the scrap yard.