USS S-9 (SS-114) was a second-group (S-3 or "Government") S-class submarine of the United States Navy.

Following duty off the northeast coast, S-9 sailed from New London, Connecticut, on 31 May 1921, and proceeded via the Panama Canal, California, and Pearl Harbor to the Philippines, arriving at Cavite, Luzon on 6 December.

On 23 June 1924, she sailed from Manila Bay and again visited ports in China before returning to Olongapo on 23 September.

Departing Mare Island on 11 February 1927, she operated in the Panama Canal area from March into April, arrived at New London on 3 May, and spent the remainder of 1927 along the northeast coast.

This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.