USS O-6, a 521-ton O-1 class submarine, was built at Quincy, Massachusetts. She was placed in commission in mid-June 1918 and conducted patrols against German submarines in U.S. East Coast waters for the next several months. When the 11 November 1918 Armistice brought an end to World War I's fighting O-6 was en route to the Azores, but soon returned home. For more than a decade, she operated in the western Atlantic and Caribbean areas, mainly on training assignments. Decommissioned in June 1931, she was laid up at the Philadelphia Navy Yard.

World War II brought the now quite aged submarine back into active service. She recommissioned in early February 1941 and went to New England waters to again perform training duty. USS O-6 was decommissioned for the second time in September 1945 and sold for scrapping in early September 1946.