Downes reached San Diego, California from Norfolk, Virginia 24 November 1937, and based there for exercises along the west coast, in the Caribbean, and in the Hawaiian Islands until April 1940, when Pearl Harbor became her home port.

The drydock was flooded in an effort to quench the fires, but the burning oil rose with the water level and when the ammunition and torpedo warheads on board the destroyers began to explode, the two ships were abandoned.

Downes sailed from Saipan 14 October to join TG 38.1 2 days later in a search for Japanese ships which Admiral William F. Halsey hoped to lure into the open with damaged cruisers Canberra and Houston.

Downes sailed the same day for Ulithi but was recalled to screen the carriers during the air strikes on the Japanese Fleet in the Battle of Leyte Gulf.

With the end of the war, Downes was ordered to return to the United States and sailed from Iwo Jima 19 September with homeward-bound servicemen on board.