 At the time of the attack on Pearl Harbor in December 1941, "Tsugaru" was assigned to support the invasion of Guam.Following the success of this mission, in January 1942, "Tsugaru" deployed from Jaluit together with "Okinoshima", under the overall command of Admiral Sadamichi Kajioka to participate in “Operation R” (the invasion of Rabaul and Kavieng).On 5 March, "Tsugaru" and "Okinoshima", under the overall command of Admiral Kuninori Marumo, were assigned to “Operation SR” (the invasion of Lae and Salamaua in New Guinea).