In January 1942, together with the rest of the First and Fifth Carrier Divisions, "Akagi" supported the invasion of Rabaul in the Bismarck Archipelago, as the Japanese moved to secure their southern defensive perimeter against attacks from Australia. She provided 20 B5Ns and 9 Zeros for the initial airstrike on Rabaul on 20 January 1942. The First Carrier Division attacked Allied positions at nearby Kavieng the following day, of which "Akagi" contributed 9 A6M Zeros and 18 D3As. On the 22nd, "Akagi"s D3As and Zeros again attacked Rabaul before returning to Truk on 27 January. The Second Carrier Division, with "Sōryū" and "Hiryū", had been detached to support the invasion of Wake Island on 23 December 1941 and did not reunite with the rest of the carrier mobile striking force until February 1942.