The first USS Scoter (SP-20), originally mistakenly designated both SP-20 and SP-53, was an armed motorboat that served in the United States Navy as a patrol vessel from 1917 until 1918 or 1919.

Scoter was built in 1916 by George Lawley & Son at Neponset, Massachusetts, as a private motorboat of the same name.

Her owner, J. L. Saltonstall of Boston, Massachusetts, delivered her to the U.S. Navy on 21 April 1917 for World War I service.

Assigned to duty with U.S. naval forces in Europe, Scoter was carried across the Atlantic Ocean on a larger ship.

Unaccounted for, she was dropped from the Navy List in 1919; she probably was disposed of in Europe that year.