Llyn y Fan Fach and Llyn y Fan Fawr

The twin lakes of Llyn y Fan Fach and Llyn y Fan Fawr lie in spectacular glacial cwms beneath the Carmarthen Fans, and this 15.3 km circular linking them showcases some of the finest mountain scenery in South Wales. Llyn y Fan Fach sits in a dramatic amphitheatre of near-vertical crags rising over 500 metres, creating a cathedral-like atmosphere of sheer rock and dark water — legend holds that a beautiful woman emerged from its waters to marry a local man, a story that has echoed through Welsh folklore for centuries. The larger Llyn y Fan Fawr reflects the surrounding peaks in its pale, cold surface. With 745 metres of elevation gain, this is a serious mountain walk.

This dog friendly walk is exceptional for fit, adventurous dogs who thrive on wild terrain. Off-lead potential is high across the upper moorland where no livestock is present, allowing dogs to range freely across some of the most dramatic landscape in Wales. Both lakes offer water access, though the water is cold and moorland streams provide better paddling opportunities. The path is steep and rocky in places, particularly around the cwm descent to Llyn y Fan Fach, demanding care in wet conditions. This walk requires good mountain fitness and navigation skills as conditions can change rapidly, but the reward is genuine wilderness that few walks in South Wales can match.