USS Adder (SS-3) (later renamed A-2), a Plunger-class submarine, was one of the earliest submarines used by the United States Navy. She was laid down on 3 October 1900 by the Crescent Shipyard, launched on 22 July 1901, and commissioned on 12 January 1903 at the Holland yard at New Suffolk, Ensign Frank L. Pinney in command.