The 9th (Service) Battalion landed at Boulogne-sur-Mer as part of the 27th Brigade in the 9th (Scottish) Division in May 1915 for service on the Western Front. The 10th (Service) Battalion landed at Boulogne-sur-Mer as part of the 46th Brigade in the 15th (Scottish) Division in July 1915 for service on the Western Front. The 11th (Service) Battalion landed at Boulogne-sur-Mer as part of the 77th Brigade in the 26th Division in September 1915 for service on the Western Front but sailed for Salonika in November 1915.