On 25 April, "Witter" departed the southern Solomons in company with Task Unit (TU) 34.9.6, bound for Cape Gloucester on the island of New Britain in the Bismarck Archipelago. She arrived in Borgen Bay near Cape Gloucester on 28 April and remained until 1 May when she accompanied TU 34.9.6 to the Russell Islands subgroup of the Solomons. She arrived in the Russells on 3 May but departed that same day for her primary theater of operations for the next 10 weeks, the island of New Guinea. On 5 May, she entered Milne Bay at the southeastern tip of New Guinea. By the time "Witter" reached that port, American forces had already made almost simultaneous landings at Aitape, Tanahmerah Bay, and Humboldt Bay, in actions known collectively as the Operations Reckless and Persecution. Thus, for the next several weeks, "Witter" drew duty escorting resupply and reinforcement convoys to the three landing areas, making stops at such intermediary places as Cape Cretin and Cape Sudest. After the 17 May assault on the Toem–Wakde–Sarmi area located a little farther up the northern coast of New Guinea, she added that region to her itinerary. At the end of the first week in July, Biak Island, located off the northern coast of New Guinea, opposite the large bay which separates the Vogelkop from the rest of the island, came within "Witter" 's sphere of operations.