How To Visit Pen y Fan’s Secret Waterfall (Nant Sere Waterfall)

Just to the north of Pen y Fan, in Cwm Sere, there is a series of cascades and waterfalls collectively known as the Nant Sere Waterfalls. The Nant Sere (river) flows off the eastern flanks of Pen y Fan and into the valley below.

Near the head of the valley the Nant Sere Waterfalls, also known as Pen y Fan’s secret waterfall, offer a beautiful climax to walk along Cwm Sere (Sere Valley). This easy to moderate walk can be completed in just a few hours, although more time is needed to relax at the falls or enjoy a refreshing swim in the waterfall pools.

This is a complete guide to visiting the Nant Sere Waterfalls, with a trail description, distances, times and a video of the walk.

Nant Sere Waterfall Hiking Guide

  • Distance: 8 km return
  • Time: 2.5 – 3 hours
  • Elevation gain: 160m
  • Difficulty: Easy – Moderate
  • Starting Point: Cwm Gwdi car park (National Trust paid parking: £3 for a car, £6 for a campervan)
  • MapOS Explorer OL12 Brecon Beacons National Park
  • How to pronounce: Nant Seh-reh

There is no public transport to the start of this walk so private transport is required. If possible, park in the lower part of this car park as this is where the trail starts. Click on this link to see the starting location on Google maps

This is a stunning waterfall walk in the Brecon Beacons (Bannau Brycheiniog) which is mostly devoid of crowds who typically hike the nearby route up Pen y Fan. The route meanders through an ancient woodland, around an impressive ridge and along a gorgeous valley before reaching the picturesque waterfalls. This trail isn’t signposted but is mostly straight forward to navigate, particularly in clear weather.

To begin the walk, head towards the pay and display terminal and take the small path into the woods on the left, ignoring the signs for Pen y Fan. This path takes you through a gate and over a small wooden bridge which crosses the Nant Gwdi (river). 

The start of Nant Sere Waterfall walk
The start of this walk looks like the entrance to a fairy kingdom!

The path climbs steeply up the bank before branching away from the main path to turn immediately left. If you miss this turn you’ll be heading straight up Pen y Fan, which is a different hike altogether! After turning left, cross over the small stream and follow the path down and around to the right.

This path now begins to contour around the base of Cefn Cwm Llwch, which is the ridge you can see on your right hand side. The trail crosses several streams and gullies and can be wet and boggy during the winter months. In the summer the path is lined with ferns.

There are several trails branching off each other as you walk around the ridge, but keep the fence on your left and continue in an easterly direction. Most of the paths come out in a similar place at the northeasterly start/end of the ridge.

After around 1km the path begins to climb gradually as it starts to turn around the end of the ridge. The trail here becomes less obvious although there is a crossroads at the base of the ridge. Follow the left fork to ensure you walk the eastern side of the ridge rather than climbing up the ridge itself. Cwm Sere (Sere Valley) now begins to open up in front of you.

Struggling with all the Welsh names?! Learn how to pronounce them correctly in this guide!

The walking trail to Nant Sere Waterfall
Climbing into Cwm Sere on the side of Cefn Cwm Llwch

You now begin the 2.5 km walk along this beautiful valley. There is a gradual climb up the valley, although the path does undulate as it crosses streams flowing off the side of Cefn Cwm Llwch. In summer the ferns can reach head height in places but keep heading south towards the mountains.

As you gain height you will see two peaks dominating the skyline. On the left is the pyramid-shaped peak of Cribyn and on the right is the highest mountain in the Brecon Beacons, Pen y Fan. 

After a while you will begin to hear the thunder of the river and its cascades at the bottom of the valley on your left. Towards the head of the valley the trail forks, with the path to the left heading directly for the upper tier of Nant Sere Waterfall, which you will easily see in front of you. Walk down towards the waterfall to reach the furthest point on this out-and-back walk.

The shallow pool beneath this wide cascade is a popular spot for wild swimming and cooling off on hot days. There is a path above the waterfall where you can use stepping stones to cross over the river and admire the waterfall from the opposite bank.

Further downstream there are more cascades and a larger waterfall which shouldn’t be missed. After you’ve spent time soaking up the views at the upper waterfall, climb back up the hill and begin walking downstream, along the side of the bank. Be careful if it’s wet as the bank is very steep here.

Just a couple of hundred meters downstream you will see the larger Nant Sere Waterfall which tumbles off the edge of an impressive cliff. Give the cliff a wide birth as you skirt around the riverbank. At the base of this waterfall there is a flat piece of ground underneath a tree, which makes an ideal spot for a lunch break.

After enjoying the beauty of this hidden gem in the Brecon Beacons, climb back up the bank to reach the path you walked in on. It is possible to hike up and over the ridge, but the easiest walk out is to retrace your steps back to the car park.

Nant Sere Waterfall Walk Video

Prefer to watch rather than read? No worries! In this short video you can watch the route to Nant Sere Waterfalls, as outlined in the description above.

Related Reading

What to pack for a walk to Nant Sere Waterfall

For a complete packing list of what I take for a day in the mountains, take a look at this article.

Accommodation Options Near the Secret Waterfall

The nearest town to this hike is Brecon. Brecon is a pretty little market town with lots of independent places to stay and is a good location for many walks around the Central Beacons. The beautiful Camden Lodge B&B offers exceptional service, with large, clean rooms that have delightful views over the hills. Cefn Cantref is a perfectly placed campsite for this walk or if you need a hostel, the closest is YHA Brecon Beacons in Libanus.

Final Thoughts on Walking to Nant Sere Waterfall

Nant Sere is a series of waterfalls on the river Sere in the Brecon Beacons of South Wales. The river flows off the northeasterly flanks of Pen y Fan into the Cwm Sere (valley) below. Hikers are able to visit these scenic waterfalls through embarking on an 8km walk from the Cwm Gwdi car park.

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. Thank you! This helps cover the cost of running this blog and keeps all resources free to access 🙂

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Louise is an Adventure Tour Guide, Snowboard Instructor & Mountain Leader from South Wales. Through working as a tour guide and snowboard instructor, she has spent the last 15 years travelling Asia, Africa and the Americas. Louise is a published photographer and currently guides mountain trips in the UK.

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