Commissioned on 13 January 1922, Sepulga was decommissioned on 15 April 1922, and laid up at Mare Island for the next 18 years.

Based at San Pedro, she carried fuel, general cargo, and passengers from the west coast to Guam, the Philippines, Wake Island, Midway, and Hawaii during the remaining months of peace in the Pacific.

After reaching San Pedro on 5 August, she again departed her California base on the 24th and headed north to Dutch Harbor in the Aleutians where she dispensed petroleum products into the fall, interrupting those duties only for runs to the Seattle area to refill her tanks.

Temporarily assigned to ServRon 4, she arrived at Funafuti on the 15th; took on Navy and Marine passengers; and, on the 23d, got underway for Kwajalein.

Later reassigned to ServRon 10, she remained at Kwajalein into June; then moved to Eniwetok to provide similar services, to serve as receiving ship for passengers in transit, and to act as headquarters for the fuel section of her squadron.