En route on 29 May 1942, the S-boat received orders to patrol the southern approaches to Umnak Pass in anticipation of a Japanese attack. On 2 June 1942, she took up her station. The next day, the Imperial Japanese Navy sent carrier planes against Dutch Harbor (commencing the Battle of Dutch Harbor 3–4 June 1942) and landed troops on Kiska and Attu Islands. The war in the Aleutians had begun.