On 16 December,
Triton got underway for a position east of Wake on the Midway–Wake route. She was one of three submarines stationed between the two islands to mark the way for
United States Army Air Forces B-24 Liberator bombers in strikes on Wake and to rescue the crews of any planes forced down at sea. She made no rescues, but, on the night of 23 December, she aided in guiding the Liberators in a night bombing attack on the island. On 24 December, the submarine sighted the mast of a ship on the horizon, headed for Wake anchorage.
Triton (alerted by
ULTRA) closed to and launched two torpedoes. One hit under the
stack, the other under the foremast.
Amakasu Maru Number 1 was obliterated in a cloud of smoke and steam as she went under. The submarine then set a course for
Brisbane. On 28 December, she sighted an enemy ship, closed to , and launched three torpedoes into the transport . The ship sank almost immediately and, although there was much wreckage, no survivors were seen.
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. Three days later, she launched four torpedoes at a tanker and scored one hit. When the enemy began firing at her periscope, she went deep to begin an end around. About 20 minutes later, the submarine returned to periscope depth and launched a spread of four torpedoes. Two geysers of water rose amidships as high as the target's bridge, but no explosions followed. The next day,
Triton attempted to attack a freighter, but an escort forced her down where she was subjected to a two-hour
depth charge attack. 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. Later that day,
Triton fired her last three torpedoes at a large freighter but heard no explosions. She then headed for
Australia and reached
Brisbane on 26 January, with a total of 6,500 tons for the trip. ==Final patrol==