南西方面艦隊
On 15 March, "Ōi" was assigned to the Southwest Area Fleet and was assigned to escort two convoys from Surabaya to Kaimana, New Guinea in April, and from Surabaya to Ambon and Kaimana in May. While at Makassar on 23 June, she was attacked by Consolidated Aircraft B-24 Liberator heavy bombers of the USAAF 5th Air Force's 319th Bombardment Squadron, but she was not damaged.