St Catherine's Island

St Catherine’s Island is a small tidal island joined to Tenby by Castle beach when the tide is low. The limestone outcrop stands about twenty-five metres above the water and measures roughly two hundred metres long and sixty metres wide. A Site of Special Scientific Interest lies below the high-water mark, and the stretch of water in front is called the Catterns. The island is also known locally as St Catherine’s Rock. Its only building for many centuries was a tiny church, which had to be demolished when St Catherine’s Fort was built in 1867. The fort was constructed in the 19th century and now houses a small collection of military artefacts. A family trust has owned the island since 1962 and once ran a zoo on the site from 1968 until 1979. In 2014 the island opened to visitors for guided tours, though it closed briefly in 2016 before reopening. Part of a Sherlock episode was filmed here in 2016, using the fort as a maximum-security prison. Visitors walk across the beach at low tide to reach the island. The fort’s rooms and tunnels can be explored, and the views from the top take in Tenby’s harbour and the surrounding coastline. Tidal caves riddle the limestone cliffs, adding to the sense of adventure. The island’s mix of natural and military history offers a quiet but fascinating day out.