Llyn y Fan Fach & Llyn y Fan Fawr: A Peaceful Adventure in the Brecon Beacons
If you love peaceful walks, sweeping ridgelines, and hidden Welsh gems, this is one of those hikes that quietly takes your breath away.
Tucked deep within the Carmarthenshire Fans, Llyn y Fan Fach and Llyn y Fan Fawr sit surrounded by rugged cliffs and endless rolling hills — a pair of glacial lakes carved by time, connected by some of the most stunning scenery in the Brecon Beacons.
This is where adventure meets calm — a reminder of why Wales always feels like home for explorers and their dogs.
Getting There
The trail begins near the small village of Llanddeusant (postcode SA19 9UN). The drive in sets the tone — narrow single-track lanes, sheep wandering freely, and that unmistakable stillness of the Welsh countryside.
There’s a small gravel car park at the trailhead, free but limited, so it’s best to arrive early. There are no facilities, so come prepared: bring snacks, water, and layers for when the wind picks up on the ridge.
The Hike to Llyn y Fan Fach
From the car park, the path winds gradually uphill alongside a lively stream. It’s about 2 km to reach the lake, with a steady incline that’s easy to follow.
The views open up slowly — first rolling green hills, then steep cliffs rising dramatically ahead.
And then, as you crest the final stretch, Llyn y Fan Fach appears.
Still, cold, and impossibly beautiful. A dark mirror reflecting the mountain ridges above it.
We stopped here for a while — Lincoln sniffing at the water’s edge, Katie taking photos, both of us just letting the stillness sink in.
The Climb & the Ridge
For those looking to make the most of the day, a steep path climbs from right side of the lake up to the ridgeline of Waun Lefrith. It’s a bit of a workout, but the reward is instant.
From above, the lake looks almost unreal — a perfect oval cradled by green cliffs.
We followed the ridge towards Picws Du, pausing often to take in the views. It’s one of those trails that makes you feel tiny in the best possible way — surrounded by space, sky, and silence.
A Touch of Legend
Llyn y Fan Fach carries one of Wales’s most enduring myths — the tale of The Lady of the Lake.
According to legend, a young shepherd once saw a mysterious woman rise from the waters. She agreed to marry him, on one condition: if he struck her three times, she would return to the lake forever.
Years passed and promises broke, and after the third strike, she vanished beneath the surface, leaving behind her sons — the famed Physicians of Myddfai, known for their healing gifts.
Standing on the ridge, watching the light move across the lake, it’s easy to see how such a story was born. There’s something otherworldly about the place — quiet, timeless, and alive with mystery.
Continuing to Llyn y Fan Fawr
If you have time (and the legs for it), continue along the ridge eastwards. The trail rolls gently over Fan Foel and begins its descent towards Llyn y Fan Fawr, the second lake in this dramatic pair.
This section of the route is one to take your time with — the descent down from the ridge isn’t a simple path, it’s more of a hiker’s scramble. Expect uneven ground, loose stone, and a few moments where you’ll want to steady yourself with your hands. It’s still dog-friendly, but smaller dogs or those not used to rocky terrain might need a little help in parts.
Once you reach the lower path, the trail eases again, opening into sweeping views of the surrounding valleys with Llyn y Fan Fawr glistening below. It’s the larger and older of the two lakes, sitting beneath the shadow of Fan Brycheiniog, the highest peak in the Black Mountain range.
The contrast between the lakes is striking — Llyn y Fan Fach feels enclosed and mysterious, while Llyn y Fan Fawr feels wide, open, and calm. We followed the path around the shoreline before looping back towards our starting point.
Lunch by the Lake
Once we completed the full loop, we made our way back to Llyn y Fan Fach and stopped for lunch by the water.
There’s something about eating sandwiches beside a lake that makes them taste better — maybe it’s the tired legs, maybe it’s the mountain air. Lincoln lay beside us, eyes half-closed, tail thudding every time we rustled a crisp packet.
It was the perfect way to end the walk — peaceful, content, and surrounded by hills that feel steeped in history. You can almost sense the stories this landscape has held for centuries
Dog-Friendly Notes
This route is dog-friendly, but it’s best to keep dogs on a lead in areas with livestock and near steep drops. The ridge can get windy and exposed, so take extra care if visibility drops.
Take care on your route down, some paths are thinner than others - with a sheer drop next to you. On wet days, with a dog you may feel safer to avoid these routes when hiking with your dog.
Bring plenty of water for both of you, especially on warmer days — there are natural streams along the way, but they can run low in late summer. And don’t forget a towel for muddy paws… Lincoln made full use of every puddle on the descent.
What to Pack
Packing smart makes all the difference on this trail — especially with the mix of ridges, scrambles, and the occasional chance for a paddle. Here’s what we brought along (and what we’d recommend for anyone planning the same route):
Comfortable boots with good grip – essential for the rocky terrain and the scramble down to Llyn y Fan Fawr.
Waterproof layers – the weather can shift quickly in the Brecon Beacons, so it’s always worth having a jacket packed.
Water and snacks – our Fido’s Trails 3-in-1 Water Bottle was perfect for keeping both of us hydrated without carrying extra bowls.
A small first-aid kit – handy for both humans and paws, especially on longer routes.
Dog essentials – we kept Lincoln’s treats, spare lead, and waste bags neatly stored in our Fido’s Trails Dog Walking Bag.
Waterproof Long Line Lead – ideal for when Lincoln wanted to have fun and dive into the streams or have a paddle by the lake, giving him freedom to explore while staying safe.
Camera or phone – you’ll definitely want to capture the views (and probably a few muddy moments).
Where to stay
When exploring the Brecon Beacons we stay at Beacon Bluffs Escapes - its the perfect location to exploring the National Park for us, hidden away in the valleys.
Builth Wells is nestled in the heart of Wales, Bannau Brycheiniog National Park—formerly known as Brecon Beacons.
They have six ensuite, self-contained glamping cabins at Builth Wells which are located on a friendly, working farm and benefit from their gorgeous setting: after a day spent exploring the surrounding area, you might want to take a stroll on the tranquil lake shore, spot wildflowers and birds in the meadow, or walk down to the riverside for a picture-perfect picnic.
Emma & Andrew are amazing hosts - and really do look after you. Click the link below to visit their website.
Why It’s Worth It
The Llyn y Fan lakes are the kind of places that remind you why we head outdoors in the first place. They don’t have the crowds of Pen y Fan or the café stops of Storey Arms — but that’s what makes them special.
It’s just you, the trail, the wind, and the stories written in the landscape.
For us, it was one of those walks that leaves you quiet on the drive home — not from tiredness, but from gratitude.
“The great challenge of life is to appreciate the present moment — to be aware of the world around you and to marvel at its beauty.”
