At the time of the attack on Pearl Harbor, "Wakaba" was assigned as flagship of Destroyer Division 21 of Destroyer Squadron 1 of the IJN 1st Air Fleet together with her sister ships , , and , and remained in Japanese home waters on anti-submarine patrol. From the end of January 1942, she deployed with the invasion force for the Netherlands East Indies as part of "Operation H", covering landing operations at Kendari on Sulawesi on 24 January, Makassar on 8 February, and Bali and Lombok on 18 February. She returned to Sasebo Naval Arsenal at the end of March for maintenance.