USCGC Bittersweet (WLB 389) was a C or Iris-class 180-foot buoy tender of the United States Coast Guard. Built by the Zenith Dredge Company of Duluth, Minnesota, the ship was laid down on 16 September 1943, and launched on 11 November 1943. Commissioned on 11 May 1944, Bittersweet was assigned to the 17th Coast Guard District, and sailed for Alaska via the St. Lawrence River, the Panama Canal and San Francisco, arriving on 19 November 1944. Bittersweet was decommissioned on 18 August 1997, and given to Estonia. Renamed Valvas, the ship serves in the Estonian Border Guard.