USS Sebastian (AK-211) was an Alamosa-class cargo ship that was constructed for the US Navy during the closing period of World War II.

Sebastian was laid down on 10 August 1944, under US Maritime Commission (MARCOM) contract, MC hull 2165, by the Leathem D. Smith Shipbuilding Company, Sturgeon Bay, Wisconsin; launched on 21 December 1944; sponsored by Miss J.C. Sullivan; delivered to the U.S. Maritime Commission on 31 January 1945; acquired by the Navy on loan charter on 10 August 1945; converted to an AK at New Orleans, Louisiana; and commissioned on 11 September 1945.

[3] Commissioned after the end of World War II, Sebastian was retained by the Navy only briefly.

[3] She was decommissioned on 14 November 1945 and simultaneously returned to MARCOM's War Shipping Administration (WSA) for subsequent maritime service under the name Coastal Highflyer.

On 29 July 1947, she ran aground at the east end of Cayo Moa, Grand Shoal, Cuba.