The Blue Lagoon is a flooded Victorian slate quarry connected to the sea, and the colour of the water on a clear day is the kind of blue you don't expect to find in Wales. It became viral on TikTok and Instagram, but it genuinely earns it, the electric blue tones, the slate cliffs and the diving platform make it one of the most dramatic swimming spots in Britain.
Arrive early in summer or it'll be packed. The walk from Abereiddy beach takes five minutes. The water is cold, the jumping is optional, and the views from the clifftop are outstanding.