Llyn Trawsfynydd Circular

From the car park the route works around the south and west shores, past the woodland of Coed y Rhygen, on to the main dam, then through the power-station area and past the visitor centre before returning along the north and east shores to the start. The reward is the way the reservoir keeps changing character: open water and islands on one side, wooded banks on another, with mountain skylines behind. The lake is a man-made reservoir formed by dams and is the largest in Wales, so expect engineered edges alongside the scenery. One navigational note: after the power station, continue straight ahead rather than following the national cycle route signs toward Gellilydan.

Overall this sits at the easier end of moderate, though the length asks for ordinary hiking fitness. Most of the surface is made or gravel, mixed with public-footpath sections, service and unclassified roads, and a short paved roadside stretch on the A470 side. Footing is generally straightforward in walking shoes. The one sustained effort is a steep section of roughly 400 m near the main dam, and total cumulative ascent works out at around 1,250 feet across the circuit. The combination of distance, some road walking and that climb makes it more of a day out than a casual lakeside amble.

The long Trawsfynydd Lake Footbridge across the lake has been closed since structural-safety problems were identified. The most recent access-forum discussion refers to intended dismantling with no replacement confirmed, and the bridge is not a public right of way. Plan your day without it. The circuit itself remains walkable and signed, using the lakeside and road route around the water instead, which is what the 8.6 mile distance reflects.

This is a marked cycling and walking circuit, so expect to meet riders, particularly on the gravel sections. Signage is good and crowd levels are moderate rather than heavy. Treat it as a sociable, mixed-use route around a working reservoir rather than a quiet mountain path.

Waterfowl are common around the margins of the lake, and ospreys have been known to visit, though nothing is guaranteed on any given walk. Dogs are welcome on the public-footpath sections under normal Eryri rules: keep them under close control at all times, and put them on a short lead near livestock and wildlife. Where the route touches open-access land, a lead of no more than 2 m is required from 1 March to 31 July.