On 8 September, she departed Guadalcanal with Task Group (TG) 32.4, the transport screen for the Palau Islands invasion force. "Triumph" reached Kossol Passage at dawn on 15 September and began sweeping mines from the prospective anchorage there. At about 1430 on the next day, struck a mine while supporting the sweeping of Kossol Passage as destruction vessel. "Triumph" sent a fire and rescue party to assist the destroyer — by then completely without power — and took over her duties as destruction vessel destroying five floating mines by gunfire. Following that, she stood by "Wadleigh" until dark, providing what assistance she could. She then took up screening station for the night. Minesweeping operations continued on a daily basis until 18 September when "Triumph" was devoted entirely to screening and harbor control duties. She remained in the Palaus until mid-October — though at Peleliu after 30 September — and then got underway to screen a convoy to the Solomons.