As part of a major re-designation of several classes of ships, "Coontz" was redesignated guided-missile destroyer 40 (DDG-40) on 1 July 1975. The ship's next deployment was on 17 January 1976 as part of the Standing Naval Forces Atlantic (STANAVFORLANT). The force operated in Caribbean, U.S. and Canadian waters with ships from four NATO navies prior to a transit to Northern Europe where "Coontz" visited 8 countries and participated in numerous NATO exercises. Commander Howe was relieved as commanding officer by Commander Silas O. Nunn III on 6 March 1976. Nunn was later relieved as commanding officer by Commander W. P. Martin on 8 April 1978.