"Angler" began her fourth war patrol on 21 June. She paused to refuel alongside a barge in Exmouth Gulf on 24 June, and while maneuvering into position, hit an uncharted obstruction. Returning to Fremantle for repairs, "Angler" was underway again on 29 June with a new starboard propeller. She rendezvoused with "Flasher" and "Crevalle" to carry out one of the first "wolfpack" patrols of the war. The group worked the middle area of the South China Sea and along the Indochinese coast, without success. They were then ordered to move to a position off the west coast of Luzon. On 25 July, "Angler" and her sister ships picked up a large northbound convoy and began a series of attacks over the next few days. While "Angler" failed to damage any ships, the pack as a whole sank six ships for 36,000 tons. The patrol continued uneventfully until 23 August, when "Angler" returned to Fremantle.