Wild swimming in Llyn Dinas, Snowdonia

Black rainbows break in a smooth ripple as the silky water flows over my shoulders, the current gathering force as it runs towards the river. I’m swimming in Llyn Dinas near Beddgelert, one of the smaller lakes in Snowdonia.

It’s a beguiling place. The water flows glass-clear in the shallows, trembling over fine gravel. As I change into swimming gear, the electric pin of a turquoise damselfly darts and dips among the sedge. Walkers, well-clad in rustling nylon, watch me wading in, the cold slowly climbing my thighs, until the lake deepens enough to swim.

Out here the water is a lucent peaty-brown, the rocks slimy underfoot. Small fish flick between the stones, investigating my toes. Here, down at water level, I can feel the weight of the lake hanging between its tapestried shores.

Llyn Dinas is on the Glaslyn, a river known for its early runs of sea trout and spring salmon. It’s born in the blue eye of Llyn Glaslyn high on the western slopes of Snowdon, said to be the coldest lake in the UK. By the time the water has filtered down to Llyn Dinas 545 metres below, it has lost its savagery but still feels like a chill breeze.

Swimming here is an ephemeral pleasure. After 20 minutes I’ve had enough of the wind-shivered water. I haul my body’s sudden slack heaviness on to land, and enjoy the sun warming my skin, lifting the hairs on my arms as they dry.

A pair of stonechats clink on the hillside above and grasshoppers zither in the grass. To my left a snaggle of bramble holds a few gleaming blackberries, the first this year. They taste winey, sharp and full of tannin, rain-ripened in the recent storms.

Behind me is the continual rush and fall of the river as it funnels through the Aberglaslyn Pass and curves around the base of Dinas Emrys. Legend says this wooded hill, crowned with a dark age fort, was where Merlin saw the red dragon, symbol of Wales, defeat the white dragon of the Saxons, foretelling the coming of King Arthur.