Llyn y Fan Fach and Llyn y Fan Fawr Circular Walk Guide
Llyn y Fan Fach and Llyn y Fan Fawr Circular Walk Guide

Llyn y Fan Fach and Llyn y Fan Fawr Circular Walk Guide

Beautiful glacial lakes, plenty of spots to take great photos and varied terrain; the Llyn y Fan Fach and Llyn y Fan Fawr circular walk has it all.

This popular, yet challenging walk is one of the best within the Brecon Beacons National Park (Bannau Brycheiniog) in South Wales.

Read on to find out what makes the walk such a great adventure, how to get there and guidance for the route.

Where is Llyn y Fan Fawr?

Llyn y Fan Fawr lies within the western region of the Brecon Beacons National Park just beyond the community of Llanddeusant. The lake sits at the base of Fan Brycheiniog, the highest peak of the Black Mountain. Llyn y Fan Fach is a couple of kilometres to the west nestled within the community of Llanddeusant.

I’ve marked both lakes on the map below and how to get to their respective car parks.

Llyn y Fan Fach and Llyn y Fan Fawr circular walk route

  • Distance: 15.1 km
  • Duration: 5-6 h
  • Summits: Fan Brycheiniog (802 m), Picws Du (749 m)
  • Difficulty: medium

I started and finished the Llyn y Fan Fach and Llyn y Fan Fawr circular walk at the roadside parking near Llyn y Fan Fawr. Therefore, I’m going to explain the route beginning and ending here. However, you can start and end at Llyn y Fan Fach car park, so I’ll touch on that option too.

Once you get up to either of the lakes, you can decide whether to walk in a clockwise or anti-clockwise direction. Terrain and steepness-wise, it’s equally challenging to walk in either direction.

I walked anti-clockwise so I could see the sunrise illuminate the face of the escarpments at Llyn y Fan Fawr.

a lake and surrounding escarpments illuminated by sunlight.

Start/end point: Llyn y Fan Fawr parking area

The roadside parking for Llyn y Fan Fawr is not officially marked on any kind of map. You can use the map from earlier in this guide to help you get there.

The parking area is opposite a stone wall lined with barbed wire. There is space for roughly 4 vehicles on the gravely section and a couple more on the grass immediately alongside the wall.

From the roadside parking you can see the River Tawe cascading down the wild moorland. Beyond this, on a clear day, you’ll be able to see the top of the escarpment above Llyn y Fan Fawr.

A river cascading down a moorland. This is the River Tawe near Llyn y Fan Fawr.

Parking area to Llyn y Fan Fawr

Begin the Llyn y Fan Fach and Llyn y Fan Fawr circular walk by leaving the roadside parking heading west. There is a grassy trail running from the parking area to Llyn y Fan Fawr through the wild moorland.

This section takes around 1 h to walk in good conditions and the terrain gradually becomes steeper. You have to cross the River Tawe, so look for a narrow passing point with large rocks to help.

It’s a good idea to keep an eye on the route map I’ve included in this post. The trail during this section of the walk is a faint path and it’s easy to stray from it even in good conditions.

In wet conditions, the ground becomes extremely boggy and so the map will be your best chance of navigating this with the least difficulty.

A moorland. There is an escarpment in the background. This is the start of the Llyn y Fan Fach and Llyn y Fan Fawr circular walk.

Llyn y Fan Fawr

The faint path brings you right to the shores of Llyn y Fan Fawr at the base of the escarpments. At this point, walk anti clockwise along the shore to the rise at the far end. Climb to the top of the rise and look back to enjoy spectacular views of the beautiful lake.

Continuing on the trail, you will now see it split into several paths: a couple heading up the escarpments and one leading around to the right. Take the lower trail leading to the right and walk away from Llyn y Fan Fawr.

Now you join a straight and flat section that’s easy on the legs. It’s also a really impressive section as the steep face of Fan Foel towers above you on the left-hand side.

A hiking trail running parallel to escarpments on the left-hand side.

At the end of this long, flat section, the trail begins to rise again. Once you reach the top of the rise, Llyn y Fan Fach will come into view in the distance.

The path forks here and you can head left to walk along the base of Picws Du or continue straight before bearing left. Both paths lead to a refuge shelter on the near shore of Llyn y Fan Fach.

A hiking trail leads to a lake in the distance. There are escarpments on the left-hand side.

Llyn y Fan Fach

The grassy trail eventually joins a gravel path. This follows alongside a water irrigation system leading to the refuge shelter and Llyn y Fan Fach.

Llyn y Fan Fach is the smaller of the 2 lakes, but the overlooking escarpments are much more dramatic than at Llyn y Fan Fawr.

The shoreline of a lake called Llyn y Fan Fach. There are rocks on the shoreline.

Llyn y Fan Fach parking

To the right of the refuge shelter, you’ll see a gravel road heading down into the valley. This takes you to Llyn y Fan Fach car park.

If you decide to start the hike at Llyn y fan Fach car park, coming up this gravel road to the lake will be the first stage in your Llyn y Fan Fach and Llyn y Fan Fawr circular walk.

Picws Du (749 m)

The trail becomes much steeper at the far shore of Llyn y Fan Fach as you begin the ascent to the summit of Picws Du. Near to the top of the escarpment the views overlooking Llyn y Fan Fach are epic.

Atop the escarpment, you’ll see a pair of cairns acting as way points. Pass these and continue on to the summit of Picws Du. From the summit of Picws Du the scenery opens up giving you a panoramic view.

The breathtaking view over the national park, including the rugged escarpments in the foreground, make this one of the best hikes in the Brecon Beacons for me.

Summit of Fan Brycheiniog (802 m)

The next stage of the Llyn y Fan Fach and Llyn y Fan Fawr circular walk is to continue along the top of the escarpments to Fan Brycheiniog. The trail hugs the edge of the escarpment and continues to give you great views. You’ll also see that it’s a long way down to Llyn y Fan Fach, so I wouldn’t walk too close to the edge.

The short walk between Picws Du and Fan Brycheiniog is the most difficult part of the whole trail. There is a steep descent from Picws Du to a saddle immediately followed by a tiring ascent as you begin climbing Fan Brycheiniog. Fortunately, there are stone steps making the ascent a little easier underfoot, but it’s still a tough section.

The summit of Fan Brycheiniog is the high-point of the route and is marked by a trig point. Once again, the views are epic. You also get to enjoy Llyn Y Fan Fawr from a different perspective. On a good day, Pen y Fan and Corn Du—the tallest peaks in the Brecon Beacons—are in full view.

A path leading to a summit. There is a trig point at the summit. There is a lake below the escarpment.

Just below the trig point you’ll pass a round stone shelter. Continue past this until the path forks. You now have the option to bear right and climb again, or go left and descend. Head left and take the stone steps back down to Llyn y Fan Fawr. Walk carefully here as this section of the trail is steep and uneven.

Return to roadside parking

Finish the Llyn y Fan Fach and Llyn y Fan Fawr circular walk by heading back to the roadside parking via the faint trail.

Make sure that you follow the River Tawe and not Nant y Llyn (the stream heading in the wrong direction). Following Nant y Llyn will take you away from the roadside parking area.

It’s easy to make this mistake as the trails here all look similar. I got disorientated, took the wrong path, and had to double back on myself.

Llyn y Fan Fawr wild camping

A great way to beat the crowds to the Llyn y Fan Fach and Llyn y Fan Fawr circular walk is to wild camp at Llyn y Fan Fawr. During the summer months, when the ground isn’t boggy, the shore of the lake is a good spot to pitch a tent.

I’ve got a full guide to wild camping in the Brecon Beacons National Park. Check that out if you want some tips.

Is it safe to swim in Llyn y Fan Fach?

If you’re doing the Llyn y Fan Fach and Llyn y Fan Fawr circular walk on a hot day, then you might be tempted to swim in Llyn y Fan Fach.

Unfortunately, wild swimming here is dangerous because there are fast moving currents and hidden machinery in the lake. You’ll see signs at the refuge shelter warming against swimming.

More adventure travel advice on A World Over

The Llyn y Fan Fach and Llyn y Fan Fawr circular walk is an epic trail and definitely not one to miss if you’re exploring the Brecon Beacons.

Hopefully this guide was clear and easy to follow. Let me know in the comments if it helped you, or if not.

I’ve got plenty more guides for the Brecon Beacons on my blog. Read those to discover more epic hiking routes in South Wales.

Related: Guide to the Best Pen y Fan Walking Routes

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