The newly commissioned carrier joined Carrier Division 4, under the command of Kakuta, with "Ryūjō" on 3 May 1942. They formed the core of the 2nd Carrier Strike Force, part of the Northern Force, tasked to attack the Aleutian Islands, an operation planned to seize several of the islands to provide advance warning in case of an American attack from the Aleutians down the Kurile Islands while the main body of the American fleet was occupied defending Midway. "Ryūjō"s air group now consisted of 12 A6M2 Zeros and 18 B5Ns, plus two spares of each type. The ship transferred to Mutsu Bay on 25 May and then to Paramushiro on 1 June before departing the same day for the Aleutians.