The second USS Elfin (SP-965) was a United States Navy patrol vessel in commission from 1917 to 1918.

Elfin was built in 1911 as a private motorboat of the same name by Britt Brothers [Wikidata] at Lynn, Massachusetts.

In July 1917, the U.S. Navy leased her from her owner, Alfred W. Gibbs of Wayne, Pennsylvania, for use as a section patrol boat during World War I.

She was commissioned[1] as USS Elfin (SP-965) on 26 July 1917.

Assigned to the 4th Naval District, Elfin served on patrol duties through the end of World War I. Elfin was returned to Gibbs on 22 November 1918.