Cribinau is a small tidal island off the south west coast of Anglesey in North Wales between Porth China and Porth Cwyfan. The nearest village is Aberffraw. The island, which can be reached on foot at low tide, is notable for the 13th century, St Cwyfan's church perched on its top. The church is known locally as egwlys bach y mor (the church in the sea) or simply as Cwyfan. The church remains in use and is popular for weddings.
17th century maps show the church standing on the mainland of Anglesey but erosion by the sea of the boulder clay cliffs has since separated the church onto the island. To prevent the church falling into the sea , a protective wall was built around the church.