"Du Pont" sailed from Newport 6 May 1919 to patrol off the Azores during the historic first transatlantic airplane flight, made by Navy seaplanes, then visited Brest, France, before returning to New York 15 June. She sailed 10 July for the Mediterranean and on the 27th reported to Commander, U.S. Naval Forces, European Waters, at Constantinople, Turkey. She carried mail and passengers in connection with relief in eastern Europe, and investigated conditions in Lebanon, Syria, Egypt, and Greece. Returning to New York 21 July 1920, she was placed in reserve and operated with 50 percent of her complement in training duty along the Atlantic coast until placed out of commission at Philadelphia 19 April 1922.