At Pearl Harbor during the Japanese attack on 7 December 1941, "Montgomery" immediately began anti-submarine patrols in the approaches to the vital base, as well as inter-island convoy duty. Departing Hawaii on 11 April 1942 for Suva, Fiji, "Montgomery" began 16 months operating from Suva, Espiritu Santo, and Noumea for escort and minelaying operations in the southwest Pacific, aiding in the struggle for the Solomons. One interruption to this service was 22 September to 12 November, when she sailed north to lay mines in the Aleutians in preparation for the recapture of Attu and Kiska.