Abereiddy

Home of the Blue Lagoon, Abereiddy is a small bay on the rugged Pembrokeshire coast of west Wales, where a flooded former slate quarry has become one of Britain's most famous coasteering and cliff-diving spots.

The activity is coasteering. The Blue Lagoon, a deep, sheltered pool of striking blue-green water ringed by dark quarry walls, is ideal for the sport's mix of scrambling along the rocky shoreline, swimming through gullies and leaping from ledges into the sea. Jumps range from gentle drops to a high platform used in international cliff-diving competitions, so guided sessions can be pitched anywhere from cautious beginner to bold. Wetsuits, helmets and buoyancy aids are essential, and several local operators run trips along this stretch of coast.

What gives it character is the industrial past: the lagoon was a working slate quarry until the early twentieth century, breached to the sea when it closed, and ruined quarry buildings and tramway relics still stand above the water beside the Pembrokeshire Coast Path.

Practical detail: Abereiddy lies near the small city of St Davids in the Pembrokeshire Coast National Park, reached by narrow lanes with a modest car park behind the pebble beach. Coasteering runs mainly from late spring to early autumn, when the sea is warmer and conditions calmer; even then the water is cold and a wetsuit matters. Check tide times and swell forecasts, as this exposed Atlantic coast can turn rough quickly.