At a glance
Llyn Llydaw (LL55 4UU) — a large mountain lake at 440 m on Snowdon's Miners' Track, 1.5 miles from Pen-y-Pass. Wild swimming possible (very cold · remote · never alone). Snowdon summit directly above. Snowdon Sherpa bus to Pen-y-Pass. Arrive before 8am in summer to guarantee parking. Free.
About Llyn Llydaw
Llyn Llydaw occupies the floor of the Glaslyn cwm — the dramatic glacial cirque below Yr Wyddfa (Snowdon, 1,085 m — the highest mountain in England and Wales) — enclosed between the knife-edge ridge of Crib Goch to the north and the long dark wall of Y Lliwedd to the south. The lake sits at 440 m, its surface reflecting the summit above when the air is still, the rock red-stained with the copper mineralisation that drew 19th-century miners to this remote cwm. A causeway built for the copper mining operation crosses the middle of the lake, interrupting its surface with a narrow raised path.
The Miners' Track from Pen-y-Pass passes along the northern shore of the lake before climbing to the higher Glaslyn lake above — the blue-green water of Llyn Glaslyn at 600 m, and then the summit ridges. The Miners' Track is one of Snowdon's most popular routes, but the lake itself is reached at a point where most walkers are en route to the summit and pass without stopping — giving the waterside a relatively quiet character compared with the upper mountain. For wild swimming, the remote, cold, and dramatic setting of Llyn Llydaw is unmatched in the Snowdonia area.
Safety information
Wild swimming carries serious risks. Never swim alone. Tell someone where you're going and when you'll be back. Enter the water gradually to avoid cold-water shock. Know your exit point before you start. Wear a tow float and consider a wetsuit even in summer — Welsh lake and sea temperatures rarely exceed 16°C.
In an emergency call 999 and ask for the Coastguard (sea) or Police / Mountain Rescue (lakes & rivers). Nearest A&E: Ysbyty Gwynedd, Penrhosgarnedd, Bangor LL57 2PW. Tel: 01248 384 384.
Find it on the map
Frequently asked questions
Llyn Llydaw is reached via the Miners' Track from Pen-y-Pass (postcode LL55 4UU), the mountain pass car park at the top of the Llanberis Pass. The Miners' Track is one of Snowdon's main walking routes — a wide, well-maintained path that runs along the floor of the Glaslyn cwm. The lake is approximately 1.5 miles from Pen-y-Pass (approximately 40–60 minutes walking) at an altitude of 440 m. The path to the lake is relatively gentle compared with the upper Snowdon routes. Pen-y-Pass car park is heavily congested in summer — the Snowdon Sherpa bus (S2 from Llanberis, S4 from Betws-y-Coed) provides an alternative that avoids the parking charge and queues.
Llyn Llydaw is a large, cold, remote mountain lake at 440 m altitude — wild swimming is possible but carries significant risks. The water is extremely cold even in summer, fed by runoff from the high Snowdon ridges. The lake is remote — Pen-y-Pass is 1.5 miles away, the nearest help considerably further. Never swim alone, always tell someone your plans, enter the water very slowly to avoid cold water shock, and know your exit point before entering. The recommended wild swimming season is July and August when water temperatures are at their peak (still cold). Seek local information about conditions before visiting. The nearest A&E is Ysbyty Gwynedd, Penrhosgarnedd, Bangor LL57 2PW, tel: 01248 384384.
Llyn Llydaw sits in the heart of the landscape that made Snowdonia's copper and slate industries possible. The Miners' Track itself was built in the 19th century to serve the copper mines at Glaslyn cwm — the track, the causeway across the middle of Llyn Llydaw, and the old crushing mill building at the far end of the lake are all visible reminders of industrial activity at nearly 500 m altitude. The lake was used to process ore from the Brittania Copper Mine (Llyn Glaslyn cwm) and the red-stained rock around the old workings above the lake gives evidence of the copper mineralisation that runs through this part of Snowdonia. The dramatic aerial photograph by the Royal Air Force in 1933 of the lake and its surrounding peaks helped establish the Miners' Track as a recognised route.
Yes — the position of Llyn Llydaw, enclosed between the Crib Goch ridge to the north and Y Lliwedd to the south, gives a direct view up to the summit of Yr Wyddfa (Snowdon, 1,085 m — the highest mountain in England and Wales) at the head of the cwm. On clear days the view is exceptional: Snowdon's summit (with the Hafod Eryri visitor centre and Mountain Railway terminus visible) rises directly above the blue-grey water of the lake, with the steep cwm walls of Crib Goch and Y Lliwedd framing the composition. This view — Snowdon reflected in Llyn Llydaw — is one of the classic photographs of North Wales.
The high cwm around Llyn Llydaw is relatively sparse in wildlife terms — the altitude and cold climate limit the species present. Red grouse are found on the lower heather slopes. Ravens are regular. In summer, ring ouzels (the mountain blackbird) can be seen around the rocky outcrops. The lake itself holds brown trout and arctic charr — the charr are a relic population from the end of the last Ice Age, surviving in this and other deep, cold Snowdonia lakes. Peregrine falcons nest on the Crib Goch and Y Lliwedd crags above the lake. Wheatears are present in summer, and in autumn the upper cwm can have Dotterel (very rare) passing through on migration.