Assigned to the Atlantic Fleet, Mallard conducted minesweep duties in the 3rd Naval District through the next nine years.

Transferred to submarine rescue operations following conversion at Boston Navy Yard June to December 1928, Mallard was redesignated ASR-4 on 12 September 1929.

The next year Mallard sailed for Coco Solo, her new home port, for patrol off Panama, where she remained throughout World War II attached to Submarine Squadron 3.

During that time she performed target towing and diver training services for ships of the fleet.

In May 1946 she sailed for the east coast, arriving New York Navy Yard to be decommissioned 10 December and stripped.