 On 11 July 1945, following a month's availability at Portsmouth, Virginia, "Mattaponi" departed Norfolk for duty with the 3rd Fleet in the Pacific.She arrived at Pearl Harbor the day after the cessation of hostilities and continued on to the Carolines, anchoring in Ulithi Harbor on 28 August.With the exception of two voyages to Pearl Harbor in December 1945 and January 1946, the tanker serviced the fleet in the western Pacific until January 1947.