The 63rd (Royal Naval) Division was a United Kingdom infantry division which served during the First World War. It was originally formed as the Royal Naval Division at the outbreak of the war, from Royal Navy and Royal Marine reservists and volunteers who were not needed for service at sea, and fought at Antwerp and at Gallipoli. In 1916, following heavy losses among the original naval volunteers, it was transferred to the British Army as the 63rd (Royal Naval) Division, re-using the number from a disbanded Territorial Force division. As an Army unit, it fought on the Western Front for the remainder of the war.