"Hiyō" departed Japan for Singapore on 24 November. She arrived on 3 December and was almost immediately assigned duties as an aircraft ferry until January when the ship returned to Japan. In the meantime, the Japanese Navy had restructured its carrier air groups so that one air group was assigned to one carrier division and Air Group 652 was assigned to the 2nd Carrier Division with "Hiyō", "Jun'yō" and "Ryūhō" on 1 March. The air group was last in priority to be rebuilt and only had 30 Model 21 Zeros, 13 Model 52 Zeros and 4 D3As on hand on 1 April of its authorized 81 fighters, 36 dive bombers and 27 torpedo bombers. The ships conducted training for their aircraft in the Inland Sea until 11 May when she sailed for Tawi-Tawi in the Philippines. The new base was closer to the oil wells in Borneo on which the Navy relied and also to the Palau and western Caroline Islands where the Japanese expected the next American attack. However, the location lacked an airfield on which to train the green pilots and American submarines were very active in the vicinity which restricted the ships to the anchorage.