USS Tuna (SS-203) was a United States Navy Tambor-class submarine, serving in the Pacific during World War II and earning seven battle stars for her service.

Expending 16 torpedoes in five futile daylight attacks, Tuna pressed home determined forays only to be driven deep by intense enemy antisubmarine countermeasures.

Dispatched next to interdict traffic from reinforcing Vila Plantation and Munda, Tuna remained luckless and was forced deep and endured depth-charge attacks before ending the patrol on 7 February.

After refitting at Brisbane, Tuna set out on her sixth war patrol on 4 March to take up a position in the Bismarck Archipelago, off Lyra Reef, on the northeast side of New Ireland.

On 4 April, Tuna changed patrol zones, prowling now to the northwest of the Manus-Mussau line in the East Caroline Basin on the traffic lanes to Rabaul.

After that brush with destruction, Tuna prepared to bombard Wakde Island with her deck guns, but the presence of Japanese subchasers forced a change in plans.

On 29 July 1943, as Tuna set out from Brisbane on her eighth patrol, a Royal Australian Air Force Catalina flying boat patrol bomber attacked her, dropping four depth charges close aboard while Tuna was in the Solomon Sea 80 nautical miles (150 km; 92 mi) east-northeast of Kiriwina Island and north of Woodlark Island at 08°02′N 152°07′E / 8.033°N 152.117°E / 8.033; 152.117.

Arriving back at Fremantle on 14 October, Tuna refitted alongside submarine tender Pelias before proceeding on her ninth patrol which commenced on 7 November.

Following her ninth patrol, Tuna proceeded across the Pacific to Hunters Point Navy Yard in California, where she arrived on 6 April 1944 for a major overhaul.

In the face of the returned fire, Tuna opened up with her three-inch deck gun and scored a hit on the first salvo, holing Takima Maru near the stern.

Ten minutes later, the trawler settled beneath the waves, stern first, leaving the waters littered with secret papers and the surviving Japanese.

After commencing her 11th patrol upon departing Majuro Atoll on 15 July 1944, Tuna roamed the sea lanes of the Japanese home islands, off Shikoku and Kyūshū.

Her radar picked up tempting targets, but bad luck continued to dog the ship's efforts to make contact and launch attacks.

On occasion, the superior surface speed of the hunted enabled it to easily outrun the hunter, and good antisubmarine measures by the Japanese escort ships forced Tuna to proceed cautiously.

After moving through the Panama Canal to the East Coast, Tuna remained in commission, in the inactive fleet, to assist in the maintenance and security of other submarines sent to Portsmouth, New Hampshire, for tests.

After once again transiting the Panama Canal, Tuna arrived at Pearl Harbor on 2 March 1946 and reported for duty with Commander, Joint Task Force 1.

Underway for the United States West Coast on 7 October 1946, Tuna arrived at the Mare Island Naval Shipyard a week later where she moored with the 19th Fleet.