The impressive ruins of Oystermouth Castle is the best preserved castle on the Gower Peninsula. Open to the public during the tourist season, for a nominal entrance fee, the site can provide a good couple of hours exploration for the visitor as well as affording them with superb views over Swansea, Swansea Bay and Mumbles.
The history of the castle is intricately linked with that of Swansea Castle. In 1106, Henry de Beaumont, Earl of Warwick, became the first Norman Lord of Gower and to reward his followers he parceled out the rich farming land of his new property amongst them (building a castle for himself at Swansea in the meanwhile).
William de Londres and his family were given Oystermouth, and it was they who founded the first castle at this site, probably of a simple ringwork and bailey structure. The male line of the de Londres family ended by 1184 however, and the Lord of Gower took possession of Oystermouth Castle, adding it to the castles he already owned at Swansea, Loughor and Pontarddulais. Impressed by both its position and structure, it was not long thereafter that Oystermouth Castle became the chief residence for the Earl of Warwick and for the future lords of Gower that were to follow him.
The early fortification founded here by William de Londres, was continually modified and improved upon throughout history, as successive Welsh uprisings kept destroying their earlier counterparts. Most of the castle structure seen today dates from the late 13th century and the early 14th century.
Oystermouth Castle is also the Gower Peninsula's most haunted castle.