Converted to seaplane tender, she recommissioned 22 November 1940 and sailed for San Juan, Puerto Rico, her home port from 15 January 1941.

Returning to destroyer functions, she completed 1942 on escort duty between Trinidad and Recife and Belém, then sailed north to NS Argentia, Newfoundland, to join the offensive antisubmarine warfare patrol formed around Bogue, one of the most effective of the antisubmarine forces that ranged the Atlantic that ultimately defeated the U-boats and secured the passage of the men and goods across the Atlantic, vital to triumph in Europe.

After a convoy to Gibraltar early in 1944, Osmond Ingram served on escort duty between New York and Trinidad until June, when she entered Charleston Navy Yard for conversion to a high speed transport.

Now assigned to the Pacific, Osmond Ingram continued her war service with escort duty en route New York via Panama to San Diego, Pearl Harbor, Eniwetok, and Ulithi.

She sailed 2 April 1945 with an assault force for Okinawa, and until that island was secured, alternately escorted fast convoys to Saipan and Guam and patrolled the seaward defense lines for Hagushi Anchorage.