In 1131 Caldey Island was donated to the Benedictine monks from the Abbey of Tiron in France. In 1536 the monks were expelled from the island and it was not until 1906 that an Anglican Benedictine brotherhood bought the island and erected the present monastery. In the early 1920s it was sold to the Order of the Reformed Cistercians. The lighthouse stands on the summit of the island, not far from the old Priory, along with two dwellings which were occupied by the keepers and their families.
Trinity House converted Caldey Island Lighthouse to automatic unmanned operation in 1927; it was the last Trinity House lighthouse to be powered by acetylene gas until its modernisation in November 1997 when it was converted to mains electricity operation.
The lighthouse is now monitored and controlled from Trinity House’s Planning Centre in Harwich, Essex.