St Donats (Welsh: Sain Dunwyd) is a village and community in the Vale of Glamorgan in south Wales, located just west of the small town of Llantwit Major. The community includes the village of Marcross and the hamlets of Monknash and East and West Monkton. It is named after the 6th century saint, Dunwyd, a friend of Saint Cadoc. It has a population of 686.
St. Donat's church lies in a depression and is unremarkable from the exterior but contains Stradling monuments.
The village is internationally known as the location of the 12th century St Donat's Castle which is now an international boarding school occupied by Atlantic College, the first of twelve United World Colleges. Within the castle grounds lies St Donat's Arts Centre.
Saint Donat (Sveti Donat, Saint Donatus) (second half of 8th century - Zadar, Croatia first half of 9th century) was Dalmatian bishop and a diplomat of city of Zadar.