Based at Eniwetok, the tanker fueled many types of ships—mainly amphibious craft, PC's, and minecraft—from 8 July through the end of hostilities in the Pacific Ocean.

After the surrender of Japan, ServDiv 102 received orders to Tokyo Bay to fuel smaller units of the occupation forces.

With a full cargo of diesel and lubricating oils, Waupaca got underway on 7 September, as part of Task Unit (TU) 30.9.21, and proceeded for Tokyo Bay.

En route, lookouts sighted a floating, drifting, horn-type mine and notified the Officer in Tactical Command (OTC) of TU 30.9.21, who dispatched a patrol craft to investigate -- PC-825 soon sank the navigational hazard with gunfire.

Waupaca anchored off Yokosuka, Japan, on the 21st, and shifted alongside the damaged Japanese battleship Nagato on the 30th to serve as a fueling station.