The first of her eight war patrols began 18 August and took her into the East China Sea where she twice attacked the enemy, inflicting undetermined damage to several ships before returning to Pearl Harbor 6 October.

Her mission, to destroy enemy ships in the Philippine and Celebes Seas areas was carried out with several attacks, one of which sank an ex-net tender.

From 3 September to 7 October she ranged the South China Sea, pressing her attacks to damage several Japanese ships and to sink two more, including a minelayer.

From Exmouth Gulf she continued alone into the South China Sea where she found that increased allied air activity had further diminished use of the shipping lanes.

Following this action she received from escorts the worst depth charging of her career, but escaped without serious damage, and returned to Australia 21 December.

Pargo then sailed via Saipan and Pearl Harbor to Mare Island for a modernization overhaul which lasted from 25 March to 17 June.

Returning to Pearl Harbor with the knowledge that she had contributed materially to the victory in the Pacific, Pargo assumed post-war duties as part of the squadron based there.