4 Walking Routes to Llyn y Fan Fach & Llyn y Fan Fawr

Llyn y Fan Fach is a glacial lake in the Brecon Beacons. This hiking guide describes 4 walking routes which take in views of this beautiful lake. I provide trail descriptions, distances, times and starting locations.

Picws Du mountain and Llyn y Fan Fach lake

The Black Mountain (singular) refers to a range of mountains in the Western Brecon Beacons National Park. This is not to be confused with the Black Mountains on the Eastern side of the Park.

The highest peak in the Black Mountain (Y Mynydd Du) range is Fan Brycheiniog at 802m. This range of mountains displays breath taking examples of glacially formed cwms (or valleys), lakes and escarpments.

For me this remote western side of the Brecon Beacons offers the best Beacons walking and attracts very view visitors, compared to the Central Beacons and the Black Mountains in the East.

For years locals have revelled in having this glorious spot on their doorstep but in 2020 it seems the secret is out, after appearing on the BBC’s Secret Britain and being voted the UK’s number 1 Hidden Gem by Hayes and Jarvis.

For information on other top hikes in the Brecon Beacons, click here!

Purchase beautiful images of the Brecon Beacons here

Black Mountain Walks

There are multiple walking routes that allow you to enjoy the Black Mountain range and views of Llyn y Fan Fach. Below I outline four walks of differing lengths that explore this beautifully secluded region.

1. Llyn y Fan Fach Walk 

  • Distance: 8 km 
  • Time: 3 hours
  • Starting Point: Llyn y Fan Fach Car park, Llangadog, Llanddeusant SA19 9UN

From the car park follow the path that heads east and then south, following the river – Afon Sawdda. This is a gradual climb past multiple waterfalls, that leads to a beautiful reveal of Llyn y Fan Fach.

Tip: If you want an easy Llyn y Fan Fach walk, simply retrace your steps from here and walk back to the car park. This is a short 4km loop.

After enjoying some time soaking in this great amphitheatre, continue around the lake to the west and ascend the ridge.  The views from the top of this dramatic escarpment are well worth the climb.

Follow the path along the ridge to the north-east, keeping views of the lake down to your left. Climb to Picws Du (Bannau Sir Gaer) which is the second highest peak in this range, before dropping down into the saddle.

At this point bear left down a steep gulley trail which zig zags down the escarpment. Once at the bottom, take the trail to the left to head back in the direction of the lake. Follow the riverside path back down the valley to the car park starting point.

This is a great Llyn y Fan Fach short walk that provides incredible views in all directions, however the path down from Picws Du is very steep with loose scree and is not suitable for children.

Looking down on Llyn y Fan Fach

2.  Llyn y Fan Fach and Llyn y Fan Fawr circular walk 

  • Distance: 15 km
  • Time: 6 hours
  • Starting Point: Llyn y Fan Fach Car park, Llangadog, Llanddeusant SA19 9UN

From the car park follow the path along the Afon Sawdda to reach the first lake of the hike – Llyn y Fan Fach. At this point leave the gravel trail and take the path to the right of the lake to ascend the ridge.

At the top continue along the ridge path with magnificent views of the lake down to the left. After reaching the high point on this ridge of Picws Du (Bannau Sir Gaer), descend the saddle before climbing back up steeply to the next ridge.

The most northerly point of this peninsula is Fan Foel at 781m which is marked with a cairn. At this point the trail heads in a southerly direction and you can now see the second lake of this hike, Llyn y Fan Fawr.

Views of Llyn y Fan Fach
Looking back towards Picws Du and Llyn y Fan Fach

Continuing along the path you will next reach the highest point on this hike and indeed in this region – Fan Brycheiniog. At this point on clear days, you will be rewarded with fabulous views of the highest peak in the Brecon Beacons, Pen y Fan.

Discover my favourite routes to the summit of Pen y Fan in this guide.

Leaving Fan Brycheiniog, the descent begins. 600m after leaving the peak a path breaks off to the left to steeply descend down to the lake.

Standing above Llyn y Fan Fawr
Walking down the steep path to Llyn y Fan Fawr

Once at the lake, take the path that veers off to the left and circles the eastern side of the lake. Follow this path to the northern end of the lake before taking the path on the left that leads towards to base of the escarpments.

Once on this path simply skirt the ridges that you walked on top of earlier, until you return to Llyn y Fan Fach. From the lake retrace your steps along the path that returns to the car park.

Not sure how to pronounce all of these Welsh words? Take a look at this post to learn how!

3. Llyn y Fan Fawr and Llyn y Fan Fach Circular Walk 

  • Distance: 20 km
  • Time: 7 – 9 hours
  • Starting Point: Tafarn Y Garreg Pub Car Park

Also known as the Carmarthen fans, this hike starts from a car park next to the Tafarn Y Garreg Pub on the A4067. This is a full day which, due mostly to the distance, is considered a strenuous walk.

From the car park, cross the road and join the footpath which immediately begins a steep ascent. This fairly quickly becomes a ridge which leads to the first summit of the day, Fan Hir. From here you will get the first views of Llyn y Fan Fawr down below.

Fabulous ridge walking towards Llyn y Fan Fawr
Walking along the ridge to Fan Hir

There is a short descent to the saddle before climbing once again to the top of Fan Brycheiniog. Continue along the ridge a little further to bag the next summit of Fan Foel, after which the trail turns in a westerly direction.

Again there is a small descent to the next saddle before climbing to the summit of Bannau Sir Gaer. Enjoying views now of Llyn y Fan Fach, continue along the ridge to take in the final peak of Waun Lefrith, before beginning the main descent.

Branch off to the right in an easterly direction to walk down to the lake. This is roughly the halfway point and a good place to take a well earned break.

Nick walking beneath the ridges towards the base of Fan Foel

The path now skirts the base of the escarpment as it continues in an easterly direction. After contouring beneath Fan Foel, the trail begins to head south towards Llyn y Fan Fawr.

Walk along the westerly edge of the lake to fully admire the beauty of the lake and then start the gradual descent back towards the car park. There are several pretty little waterfalls to admire as a final reward along the last few kilometers.

Last Minute Flight Deals!

4. Fan Brycheiniog and Llyn y Fan Fawr Loop 

  • Distance: 15.6 km
  • Time: 6 – 7 hours
  • Starting Point: Tafarn Y Garreg Pub Car Park

Follow directions for the previous hike to the summit of Fan Foel.  Enjoy views looking down onto Llyn y Fan Fach to the west and Pen y Fan to the  east. From this peak continue along the path in a northerly direction as it descends the shoulder.

Once at the base of Fan Foel, turn right and follow the path back towards Llyn y Fan Fawr. Again walk around the westerly edge of the lake and follow the trail along the gradual descent back to the car park at Tafarn y Garreg.

Lady of the Lake – The Legend

As with many places in Wales, Llyn y Fan Fach is steeped in Welsh folklore. According to this legend a young farmer was grazing his animals when a beautiful lady walked out of the water. He fell instantly in love with her. She agreed to marry him but only on the condition that he must not strike her 3 times.

They were happily married for many years and had 3 sons together. However, as you might imagine this happy story didn’t last. Versions of the myth differ as to the nature of these strikes, but sure enough the farmer did indeed strike his wife and on the third occasion, true to her word, she left and vanished back into the cold water of the lake.

There are more Welsh folklore tales linked to walks throughout the Brecon Beacons, in particular the walks in Waterfall Country.

What to pack for your hike

For a complete mountain day packing list take a look at this post, but here are some of the essentials.


Where to Stay when exploring the Brecon Beacons

There is a huge number of glamping options in the Brecon Beacons. To discover the 10 most unique and luxurious glamping spots in the Brecon Beacons read this guide!

Alternatively, a great central location for exploring the Brecon Beacons National Park is the town of Merthyr Tydfil. Merthyr is home to the epic Bike Park Wales, which provides over 40 mountain bike trails from beginner to advanced.

To discover all the other adventurous activities to enjoy in Merthyr Tydfil, take a look at this post.



Disclaimer: Some links in this article are affiliate links, which means that if you purchase through them I receive a small commission, at no extra cost to you. This helps cover the cost of running this blog. Thanks for your support!

Like it? Pin it for Later!

Llyn y Fan Fach is a glacial lake in the western Brecon Beacons. This is a detailed guide to hiking Llyn y Fan Fach and Llyn y Fan Fawr.

Join My Newsletter Today!