USS O-3 (SS-64) was one of 16 O-class submarines built for the United States Navy during World War I.

[2] For surface running, the boats were powered by two 440-brake-horsepower (328 kW) diesel engines, each driving one propeller shaft.

The new submarine joined the Atlantic coastal patrol and kept watch for U-boats from Cape Cod to Key West, Florida.

After the war that had proved the worth of subs, O-3 sailed to New London, Connecticut, to train Submarine School students.

She was struck from the Naval Vessel Register on 11 October 1945 and sold to John J. Duane Company, for scrapping on 4 September 1946.