On October 28, 1941, Crotty arrived at Cavite Navy Yard in the Philippines, where he was assigned to the In-Shore-Patrol Headquarters to assist the Navy in building the Manila Bay minefield. On December 7, 1941, Japanese forces attacked Pearl Harbor and the United States entered World War II. Several hours later, across the International Date Line on December 8, Japanese troops invaded the Philippines. On December 10, Japanese aircraft bombed Cavite Navy Yard, damaging many of the facilities. Crotty was the only Coast Guardsman stationed in the Philippines and consequently the only Coast Guardsman to participate in the Philippines campaign.