"Yunnan" was requisitioned by the Royal Australian Navy on 22 June 1942 and operated in North Queensland and New Guinea waters with her civilian crew. She was commissioned into the Royal Australian Navy as HMAS "Yunnan" on 20 September 1944 and sailed as part of the supply force for the Leyte campaign, then sailed for Hollandia. Although attached to the supply force for the military landings at Lingayen Gulf, "Yunnan" was not present at the landing. During the later part of 1945, she operated in New Guinea, Admiralty Group, Morotai, Tawi Tawi and the Philippines area, before returning to Sydney and was paid off on 31 January 1946.