The Blue Lake – Gwynedd, Wales - Atlas Obscura
The Blue Lake is permanently closed.

The Blue Lake

A hidden tunnel leads to an abandoned slate quarry that's now a secret swimming spot guarded by cliffs. 


There’s a hidden lake in Snowdonia National Park, guarded by towering crags. Only those who stumble upon the tunnel built into the hillside or abseil the cliffs can access the water, which is remarkable for its rich blue color.

Those who do manage to wander through the tunnel will find themselves emerging right along the water’s edge. A narrow path skirts two sides of the lake at the foot the vertical cliffs. According to local rumors, the lake is deeper than its height above sea level.

The lake is in fact a slate quarry. It opened in 1867, though it was eventually flooded and in an ill-fated plan to turn it into a reservoir for hydroelectricity. A smattering of industrial archeology surrounds the site, left over from the lake’s original quarrying days. Stirred up minerals add to the water’s bold color.

Some say the secret spot is one of the best places for wild swimming, though the water is often quite chilly and the slippery terrain makes getting in and out of the water dangerous. The nearby plateau offers stunning views of Barmouth Bay.

Update May 2019: The property owner has obstructed access to the lake due to littering and general disregard for the environment. The entrance tunnel has been filled in.

Know Before You Go

The lake is on private property. Those who still choose to visit do so at their own risk.Driving from Dolgellau to Fairbourne on the A493, go 1/2 mile past the Fairbourne turn until you see a phone box on the right. Turn onto the road opposite the phone box and park. Then walk up the road until a footpath is signed off to your right, follow this footpath until it turns sharp left over a stile. At this point carry straight on onto a flat plateau area, the tunnel entrance to the lake will be on your left.

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