USS Triton (SS-201) was the fourth Tambor-class submarine to be commissioned in the United States Navy in the years leading up to the country's December 1941 entry into World War II.

She was the first submarine and third ship of the United States Navy to be named for Triton, a mythological Greek god, the messenger of the sea.

Nine days later, she and sister ship USS Trout (SS-202) headed for Hawaii and arrived at Pearl Harbor on 4 August 1941.

Assigned to Submarine Division 62,[11] Triton made a training cruise to Midway from 30 August to 15 September, then participated in local and fleet operations in the Hawaiian area.

When the Japanese ship slowed astern, the submarine came to 120 feet (37 m) and fired four stern torpedoes—the first American torpedoes shot during World War II—on sonar bearings.

)[13] After their initial repulse on 11 December, the Japanese returned with two aircraft carriers, Hiryū and Sōryū; Triton was not informed,[14] and made no attacks on them.

On 25 January 1942, Triton got underway for the East China Sea and her second war patrol, covering the sealanes to Dairen, Shanghai, and Korea.

She sank Shokyu Maru with two torpedoes but could not attack the second ship because of its speed and the appearance of a four-engine patrol plane.

[18] After missing with two torpedoes (at point blank range),[18] she surfaced to engage with her deck guns, firing 19 rounds of three-inch (76 mm) and "a hurricane of small-arms",[18] leaving the trawler a sinking wreck, giving Triton the first confirmed sinking of an enemy vessel by deck gun fire by an American submarine.

Amid shallow, glassy seas and poor sonar conditions,[18] on 1 May, she sighted six freighters, in two columns, escorted by a single[18] torpedo boat.

She launched two torpedoes, and both hit the leading ship, Taei Maru (2,200 tons), which sank,[18] then two more at the next freighter; both missed.

Triton contacted an escorted convoy on 6 May and launched two torpedoes at the trailing ship; one sank soon after leaving the tube, the other missed ahead.

[18] She next spotted a destroyer coming to the rear of the convoy, fired two more (both set shallow) at this same ship from 1,200 yards (1,100 m), and went deep to elude.

Triton heard two explosions from the first spread (one in the third ship), none from the second (which had avoided),[18] as she was forced to take evasive action from the escort.

The next day, after monitoring orders to other boats attempting to intercept without success, Triton ran into position[19] and at 15.20 spotted the crippled Shōkaku and a destroyer, returning from the Battle of the Coral Sea.

One day later, 17 May,[21] in "one of the luckiest finds of the war",[20] I-64[18][22] surfaced right in front of Triton; she fired her last bow torpedo from 6,200 yards (5,700 m) and parts of the target were blown 100 feet (30 m) into the air.

The patrol earned her credit for five ships of 24,200 tons (reduced to 15,800 postwar),[24] terminating at Pearl Harbor on 4 June, as the Battle of Midway began.

Triton was then ordered to patrol the Truk–Rabaul–New Guinea shipping lanes, north and northwest of New Ireland, arriving on 30 December 1942.

On 10 January 1943, Triton stalked an unidentified vessel but withheld her attack upon observing it was marked as a hospital ship.

On 16 January, she attacked two cargo ships, scoring two hits on the first and one on the second; but her victims forced her to submerge before she could evaluate the damage.

[31] Falling under the strict tactical control of Admiral James Fife, Jr.,[32] Triton (now in the hands of George K. MacKenzie)[32] on 16 February began her sixth and final war patrol, hoping to destroy enemy shipping between the Shortland Basin and Rabaul.

On 13 March, Triton was warned that three enemy destroyers, including the Akikaze were in her area either looking for a convoy or hunting American submarines.

Triton is the subject of an episode of the syndicated television anthology series, The Silent Service, which aired in the United States during the 1957–1958 season.