The Aleutian Islands campaign began on 3–4 June 1942 with a Japanese air raid on Dutch Harbor, Alaska, followed quickly by the unopposed Japanese occupation in the Aleutian Islands of Attu on 5 June and Kiska on 7 June 1942. On 11 June 1942, "I-2" set out for Aleutian waters in company with "I-1", "I-3", "I-6", and "I-7" to begin her third war patrol. On 20 June 1942, "I-1", "I-2", and "I-3" joined the "K" patrol line in the North Pacific Ocean between and . Refueling from the oiler on 24 June 1942, she remained on the patrol line until 3 July 1942. On 17 July 1942, she attacked an unidentified Soviet merchant ship with gunfire south of Dutch Harbor, but a U.S. Navy PBY Catalina flying boat drove her off. On 20 July 1942, she was reassigned to the Advance Force and ordered to return to Japan. She arrived at Yokosuka on 1 August 1942 and underwent repairs there.