"Rockford" then returned to New Guinea, remaining there until 15 October 1944, when she began a voyage to the United States West Coast via Manus Island and Pearl Harbor, Territory of Hawaii.On 13 November 1944, during the final leg of the voyage, "Rockford" and the minesweeper attacked and sank the Japanese submarine "I-12" midway between Hawaii and California; there were no survivors from "I-12".