St Tudwal's Island East (Welsh: Ynys Tudwal) is a grass covered, privately owned, kidney-shaped island, about 500m in length and 200m in width.
The highest point on the island is 38m. It is located just over 1km off the Lleyn peninsula in Wales, specifically at Latitude 52:48:21N, Longitude 4:27:51W. The nearest settlement (apart from the lighthouse on Saint Tudwal's Island West) is Machroes. The surrounding waters are good for fishing, and small ships sail from the nearby town of Abersoch to take passengers to view the wildlife. The island is believed to be the original hermitage of Saint Tudwal, which is presumably where its name comes from. The remains of a priory, referred to in the 1291 tax rolls, can be found on its eastern side.