Launched 25 November 1917 at Fore River Shipbuilding, O-6 was commissioned on 12 June 1918. She operated out of Philadelphia during the rest of World War I and, with O-4, was shelled in error by a British freighter on 14 July 1918, sustaining no serious damage. Detailed to Europe at the beginning of November 1918 as part of a large contingent, she returned to the United States before completing her crossing after the war ended.
During the 1920s, 0-6 served as a training boat at New London, with the usual O-boat deployment to Coco Solo in 1924. She was decommissioned 9 June 1931 at Philadelphia.
On 4 February 1941, O-6 was recommissioned and returned to New London, where she would serve as a training boat during World War II. On 20 June 1941, she participated in the search for O-9, which was lost off Portsmouth, NH.
When the war ended, O-6 was decommissioned and stricken on 11 September 1945. She was scrapped in December 1946.
Builder: Fore River
Sponsor: Mrs. C.Q. Wright
First Captain: LT C.Q. Wright, Jr.