A sea-water lake on Weston-super-Mare's seafront, held back by a causeway so you can swim even when the tide is far out
Open accessfree and open all year — unheated sea water, so check the conditions before you get in
Weston-super-Mare’s tide goes out a very long way across the mud of the Severn Estuary, and Marine Lake, built in 1929, keeps a body of sea water in place for swimmers at any state of the tide. The lake fills a cove beside Knightstone Island, held in by the Knightstone Causeway, with sluice gates to manage the level, and the sea tops it up whenever the tide comes over the causeway. North Somerset Council, which runs it, calls it the largest recreation pool of its kind in the country. Marine Lake is free, needs no booking and is open all year for swimming and non-powered watersports. The water is unheated sea water, and the lake reopened in 2026 after a refurbishment. You Can Sauna is a few steps away on the seafront, and the Grand Pier is a short walk south-east. Weston-super-Mare station is about 1.5km south-east.
