← Dive-sites: Llyn Arenig Fawr


Llyn Arenig Fawr is a reservoir which sits near the summit of Mt. Arenig Fawr, an 854m mountain in Gwynedd. No diving is permitted at this site. It is an active reservoir which is used to supply water to Bala, as well as other small villages. Immediately to the west is the summit of Pen Tyrau, which seems to give the reservoir a dark shadowed appearance.

Llyn Arenig Fawr is situated on farm-land and thus there is no vehicle access. It is roughly 2km from the nearest parking spot, just by the start of the foot path. The trail is in good condition and has some great views, including views of Afon Tryweryn from above.

If it were a dive-able site, it might have proven difficult to get to while carrying cylinders and kit.


Arenig Fawr from footpath

Arenig Fawr from footpath

Key Metrics

RegionPersonnel AccessRoad AccessDepth (m) *Permission neededLat Long (DD)Elevation (m)
Gwynedd (E)1/5 Difficult4/5 GoodNo Diving52.927211,-3.717150407

Site Maps

Arening Fawr Map

©OpenStreetMap contributors


(Click the ‘Lat/Long’ data in the ‘Key Metrics’ section for Google Maps directions)
By road – To get to the parking space, follow the small road which peels off from the A4212 (a road that passes Afon Tryweryn). The road itself isn’t named. You will pass a large quarry on your right and pass between a narrow gap which appears to be some old quarry workings (The quarry may be of worth to explore too!). Soon you will reach a point where you can park by the side of the road, with a large metal gate and walkers gate on the right hand side of the road.
To the water – The first section of the walk is fairly steep, but the track is good. Simply follow the path for roughly 2km to get to the edge of Llyn Arenig Fawr and the dam. Following the path further will take you to the summit of either Pen Tyrau or Arenig Fawr

Arenig Fawr warning signs

Arenig Fawr warning signs


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