In a flooded former slate quarry, the shockingly turquoise Blue Lagoon is a magnet to brave wild swimmers who don't mind the water being deep and bitterly cold. Slate was quarried at this site on the water's edge in Abereiddi up until 1910 and then transported by tramway to the harbor at Porthgain. After the mining stopped, a channel was blasted through to the sea, creating this brilliant blue-green pool surrounded by a bowl of sheer stone walls.
From Porthgain, the Blue Lagoon is best reached via a spectacular 30-minute walk west along the coast path, past the ruins of workers' cottages and quarry buildings.
