Coghlan sailed from San Francisco on 22 September 1942 for Pearl Harbor and Kodiak, Alaska, arriving on 13 October for convoy and patrol duty.

She supported Army landings on Amchitka on 12 January 1943, and participated in the bombardment of Gibson Island at the entrance of Chicago Harbor on 18 February.

On 15 March she cleared Dutch Harbor with a force to patrol against Japanese shipping south and west of Kiska to prevent reinforcement of Japanese-held Attu.

In this action, Coghlan screened Richmond, and laid smoke for Salt Lake City; she was hit once by a Japanese shell, but sustained no casualties.

Overhauled at San Francisco in July, Coghlan returned to Adak on 13 August for 2 final weeks on patrol in the Aleutian Islands.

Coghlan sailed from Pearl Harbor 22 January 1944 to screen aircraft carriers giving air coverage to the landings in the Marshall Islands.