When Italy entered World War I, on 24 May 1915, Tur was the executive officer of the destroyer "Irrequieto". He soon obtained his first command, a torpedo boat in the Northern Adriatic Sea. For an action with his torpedo boat off the coast of Pola, he was awarded a Bronze Medal of Military Valor. In June 1917 he was promoted to Lieutenant Commander, and in March 1918 he was given command of the "Caorle" Battalion of the Marine Regiment, deployed on the Piave River. In command of the "Caorle" Battalion, Tur participated in the Second Battle of the Piave River and the Battle of Vittorio Veneto, receiving for his actions two Silver Medals for Military Valor and another Bronze Medal.