(SS64: dp. 520.6 (surf. n.), 629 (subm.); l 1724; b. 18 Ό; dr. 145; s. 14 k. (surf.), 10.5 k. (subm.); cpl. 29; a. 1 3, 4 18 tt.; cl. O1).
O3 was laid down 2 December 1916 by Fore River Shipbuilding Co., Quincy, Mass.; launched 27 September 1917; and commissioned 13 June 1918, Lt. G. L. Dickson, in command.
The new submarine joined the Atlantic coastal patrol and kept vigilant watch for U-boats from Cape Cod to Key West. In November, she joined a 20-sub contingent that departed Newport the 3d for service in European waters. However, before the ships had reached the Azores, the Armistice ended the fighting.
After the war that had proved the worth of subs, O3 sailed to New London to train Submarine School students. Reclassified as a second line sub 25 July 1924 while at Coco Solo, C. Z., and reverting to a first liner 6 June 1928, the vessel remained at New London until she moved to Philadelphia to decommision 6 June 1931.
As American involvement in World War II became imminent, O3 recommissioned at Philadelphia 3 February 1941 and sailed to New London in June to train submarine personnel at the submarine school there until wars end. She then steamed to Portsmouth, N.H., to decommission 11 September 1945. She was struck from the Navy Register 11 October 1945 and sold to John J. Duane Co., for scrapping 4 September 1946.