Carmarthen Fans Run — Route Guide & Guided Trips
The wildest running in the Brecon Beacons: Fan Brycheiniog and Fan Hir above Llyn y Fan Fawr and Llyn y Fan Fach, with a fraction of the people you meet on Pen y Fan.
The Carmarthen Fans sit at the western end of the national park, and they feel a long way from anywhere. The escarpment runs in a long curve above two dark glacial lakes, and the running along the top edge is some of the most dramatic in Wales.
Because it is remote, it is also the route on which conditions matter most. There is no easy escape off the plateau and very few people about if something goes wrong.
At a glance
| Distance | Approximately 22 km |
| Ascent | Approximately 900 m |
| Terrain | Grass, moorland, exposed plateau edges above two glacial lakes |
| Best season | Late spring to early autumn; winter is committing and remote |
| Difficulty | Hard — remote, exposed and much quieter than the central Beacons |
| Start point | Llanddeusant or the Tafarn-y-Garreg side of the Swansea valley |
| Region | Brecon Beacons |
| Guided | Yes — quoted against dates and group size, request a quote |
The route, section by section
| Section | What to expect |
|---|---|
| Approach to Llyn y Fan Fach | Gentle track running in, with the escarpment building ahead of you |
| Climb to the ridge | Steep grass and stone onto the plateau edge |
| Fan Brycheiniog to Fan Hir | Long, exposed edge running — the highlight of the whole route |
| Descent and return | Off the escarpment and back around below the crags |
Route notes and safety
Exposed from the moment you reach the ridge, with a steep drop on the lake side. Mobile signal is patchy. Treat this as a full mountain day: proper waterproof, warm layer, food and the ability to navigate off the plateau if cloud comes down.
Running it guided
We guide this route for individuals and small groups. That means route planning, navigation, pace matched to you, safety kit and first-aid cover carried by the guide, and a kit list sent before you travel. Price is quoted against your dates and group size.
- A guide on every run, with route planning and navigation
- Pace grouping, so nobody is dropped and nobody is held back
- Safety kit carried by the guide, plus first-aid cover
- A personalised kit list before you travel
- Technique and pacing coaching on trail, at no extra cost
- Accommodation and transfers bundled in if you want them
Frequently asked questions
Are the Carmarthen Fans harder than Pen y Fan?
Longer and much more remote, with a similar amount of climbing. The difficulty here is commitment and exposure rather than gradient.
Is this a good route for a first guided run in Wales?
It is a superb first guided run precisely because navigation and route choice are the hard parts — those are what a guide takes off your hands.
How busy do the Carmarthen Fans get?
Far quieter than the central Beacons. On a weekday you can run the whole escarpment and see almost nobody.
Where to go next
- Brecon Beacons trail running routes
- Pen y Fan Horseshoe
- Mountain trail running
- Trail running in the Brecon Beacons
Ready to run?
Tell us your dates, your rough weekly mileage and where you'd like to run. We'll come back with the routes we'd recommend, availability and a price.