 "Paducah" was ordered north to prepare at Portsmouth, New Hampshire, for European service in World War I, for which she sailed from New York 29 September 1917.She reached Gibraltar 27 October, and based there as convoy escort to North Africa, Italy, the Azores, and Madeira.She attacked a U-boat 9 September 1918 after it had sunk one of her convoy, and was credited with possibly damaging the submarine.