Upon mobilization and the declaration of war, the 1st Battalion, Wilts deployed to France as part of the 3rd Division's 7th Brigade, landing in France on 14 August 1914, and soon fought in the Battle of Mons and the Great Retreat and, in October, in the First Battle of Ypres, by which time the battalion had lost 26 officers and over 1,000 other ranks. The 1st Wilts remained on the Western Front with the 3rd Division until the 7th Brigade was transferred to the 25th Division on 18 October 1915. In March 1918 the battalion was involved in Operation Michael, the opening phase of the German Army's Spring Offensive, and subsequently reduced to company strength. It was during this fighting that Acting Captain Reginald Frederick Johnson Hayward MC was awarded the Victoria Cross. The 1st Wilts served with the 25th Division until was transferred on 21 June 1918. On 21 June 1918, the 1st Wilts joined the 110th Brigade, part of the 21st Division, with which it served for the rest of the war.