USS C-1 (SS-9) was the lead ship of her class of submarines built for the United States Navy in the first decade of the 20th century.

Assigned to Submarine Flotilla 2 (SubFlot 2), Octopus operated out of Newport, Rhode Island and New York City until 9 October 1908.

Tests and experiments, of both submarine design and the tactical use of her type, continued from Norfolk, Virginia and Newport until she was placed in reserve at Charleston, South Carolina on 14 February 1910.

C-1 was reassigned to Submarine Group 1, Torpedo Flotilla, Atlantic Fleet, and from 29 May – 7 December operated out of Guantánamo Bay, Cuba.

She served in Panamanian waters in training, and later, on patrol during World War I until 4 August 1919, when she was decommissioned at Coco Solo in the Panama Canal Zone.