Llyn Clywedog Trout Fishing | We Review This Mid Wales Fishery

James
Jul 28
7 min read

Updated: 4 days ago

LIyn Clywedog reservoir

LIyn Clywedog Fishing Quick Summary

Llyn Clywedog fishing is a proper mountain reservoir sitting high up in the Cambrian Mountains, over 900 feet above sea level and just 4 miles outside Llanidloes in Powys. Spanning 615 acres and reaching depths of over 200 feet, it’s held back by the massive 236 foot Clywedog Dam wall, the tallest concrete dam in the UK.

Run by the Llanidloes & District Angling Association, they stock around 35,000 to 40,000 quality trout every year, including hard-fighting Rainbows, Blues, Tigers, Browns, and native wild trout. Because it’s high up in the hills, the water stays nice and cool right through the summer, giving you cracking top water fly fishing, top-notch boat drifting, and plenty of bank sport all season long.

It anchors a great Mid-Wales campervan loop. You can fuel up with breakfast in Llanidloes before heading up to fish the reservoir, move on through Rhayader for a morning stop at The Lost ARC cafe on the way to wild camping at Coco's, pick up local cider at Welsh mountain cider along the route, and end the day parked up at camp with the barbecue going.

Fly Fishing Scorecard

Fish Quality: 🎣🎣🎣🎣🎣
Setting & Views: 🎣🎣🎣🎣🎣
Value for Money: 🎣🎣🎣🎣
Facilities: 🎣🎣🎣
Accessibility: 🎣🎣🎣
Café / Food on Site: 🎣 (Snacks/drinks in lodge)

Type: Reservoir / Stillwater
Day ticket price: £29 (Full Day)
Catch and release: Yes
Stocked: Yes (35,000+ per year)
Overnight camping: No
Best flies: Black Buzzers, Coch-y-bonddu Beetle, Cormorants, Diawl Bachs, Montanas
Nearest town: Llanidloes, 4 miles
Best for: Beginners / Intermediate / Advanced / All levels
Website: Home - Llyn Clywedog Trout Fishing

Where We Stay & Eat: Llanidloes & The Journey Home

The whole trip is a big loop around. On the drive out, we usually stop off at Foxholes castle campsite, and on the way back from Rhayader, we’ll stay over at Coco’s Wild Camping to break up the journey. Having fished Clywedog Reservoir three times now, Llanidloes is always our go-to base. It’s the closest town to the water, full of character, and packed with decent pubs, coffee shops, bakeries, a deli, and a proper butcher.

Before heading up to the reservoir, a proper, heavy-duty breakfast is essential since there isn't hot food available at the water. After trying a few places around town, Hiraeth on the High Street, located in the old butcher's shop, is easily our top pick.

At £13.95, their full Welsh breakfast scores a solid 8.5 out of 10. You get two slices of bacon, a sausage, black pudding, a hash brown, baked beans, a grilled tomato, mushrooms, a local free-range egg, and thick-cut toast from Andy’s Bakery. All the meat is sourced locally from The Prized Pig Company. The sausage and bacon are excellent, but the black pudding is honestly one of the best I’ve ever had, so good that I’ve actually started ordering their chilli-flavoured black pudding online at home. They also run great lunch and evening menus if you're hanging around town later in the day and don't fancy a curry.

After a full day on the reservoir, we head back into town for a well-earned debrief. Our go-to spot for a few post-fishing pints is The Mount Inn. We always head straight to the beer garden, which is usually buzzing and packed with local atmosphere.

When it comes to dinner, Llanidloes has two curry houses: Raj Mahal and Sylhet Bangladeshi Restaurant. Having tried both, Sylhet takes the top spot for us. The rotis are solid, but their Meat Bhuna ordered with extra green chillies is my go-to dish.

We always make a point to swing by Welsh Mountain Cider just outside town to pick up a few bottles to take home. Hands down, it’s the best cider produced in the region. They also run a fantastic back-to-basics campsite set right in the orchards with incredible views across the Cambrian Mountains, which is 100% where I’ll be staying the next time I am fishing up here. Review coming.

When it’s time to head home, we usually take the scenic drive towards Rhayader rather than going straight back the way we came. We always make a point to stop at a café called The Lost ARC. It’s a fantastic, atmospheric spot with a brilliant outdoor garden where you can sit back and chill. Everything on the menu uses high quality, locally sourced ingredients, making it an absolute must visit for a post-trip breakfast or coffee before the final stretch home. We highly recommend this place.

Full English Breakfast at Hiraeth
The cafe shop front
Welsh Mountian Cider inside there barn

The Vibe & Setting Llyn Clywedog fishing

When I’m camping or fishing in Mid Wales, I always try to make a beeline for Llyn Clywedog. It offers some of the best large stillwater fly fishing Wales has to offer. Sitting high up in the Cambrian Mountains at over 900 feet, the views alone are worth the drive, but it’s the quality and pure power of the fish here that keep bringing me back.

Me and Davo have been here 3 times now, and the running score is currently 2 to me and 1 win to him! It’s always cracking getting out on the water with him, even if he spends the whole day trying to chase down my lead.

If you're planning a trip, the setup run by the Llanidloes & District Angling Association makes it straightforward for everyone whether you’re working the bank or out in a boat. The reservoir was created in the 1960s and features the imposing Clywedog Dam wall, which is the highest concrete dam in the UK at 236 feet. Because of the high altitude, the water stays cool even in the heat of summer, which means the trout stay active near the surface when other waters go quiet.

Bank anglers will find plenty of accessible stretches around the lodge and the long arms, though some areas get fairly steep. If you prefer boat fishing, they operate a massive fleet of 35 Coulam 15 Defender boats fitted with 4hp Mercury motors, along with a dedicated Wheelieboat for disabled anglers.

The setup is nice and easy. You pop into the Fishing Lodge right by the boat moorings to pick up your permit, book a motorboat, or get the latest local advice on what flies are taking. You’ll find the site just 4 miles outside the market town of Llanidloes in Powys. Follow the signs up from town into the hills, and as you top the rise, the reservoir and massive dam open up right in front of you. You can park up right near the main lodge to get sorted.

add info

Tactical Advice: How We Fish It

Before heading out on the water, we always make a point to pop into the shop and ask the experts at the fishery for advice. It’s well worth doing every single time, as they know exactly what patterns and tactics are working best for that specific day or week.

Once out on the lake, drifting the open water or working down the long arms with a drogue anchor is where Clywedog really comes into its own. Early morning and late evening usually offer the best sport, and I normally run a 5 or 6 weight floating line loaded with natural patterns like buzzers, pheasant tail nymphs, or Diawl Bachs. If you hit the lake during the famous Coch-y-bonddu beetle hatch around June or July, getting a terrestrial pattern right on top produces explosive surface takes. In fact, a beetle pattern on top is what won it for me on our last trip out, though I didn't tell Davo I was using it at the time!

When the trout are sitting a bit deeper in the water column, pulling lures like Cormorants, Montanas, or Cats Whiskers on an intermediate or sinking line works wonders. If all else fails and the fishing gets tough, I always fall back on my old faithful: a blue flash damsel on a floating line.

Davo on a boat Fly Fishing in Wales
Me fly fishing with a great view
James Chilling on the boat

The Leaders that i really like are from Maxcatch

Maxcatch leaders that i use all the time,great value

Essential Fishery Details & Visitor Info

Season 2026: 12th March to 30th November.
Day Tickets: Full Day Catch & Release (up to a 6-fish limit to keep) is £29. Concessions £28, Evening tickets £20.
Boat Hire: Petrol motorboat hire is £28 for the day (£20 evening).
Rules: Strictly Fly Fishing only. Life-jackets are mandatory at all times on the pontoon and in boats. No chest waders or studded boots inside the boats.
Catch Returns: Make sure to fill in your scorecard return and drop it into the box outside the lodge before you leave!
Nearby Sights & Food: Llanidloes has some great traditional Welsh pubs like The Crown, Mount Inn and The Red Lion for a proper pint and meal after a long day on the water. If you're fancying a curry instead, head to Great Oak Street where you'll find The Raj Mahal, a local favourite offering classic Indian dishes and takeaways. You can also head down to see the base of the massive dam wall or explore the Clywedog Trail and local lead mine ruins nearby.

My Verdict:

Llyn Clywedog is a spectacular venue with proper big-water vibes. With its towering dam, deep clear waters, and dramatic hillsides, it hits you the second you push off the pontoon. It manages to strike that rare balance of being exceptionally well managed without feeling overly commercialized, giving you raw, grand Welsh mountain scenery, endless fresh air, and some of the hardest fighting trout you’ll hook anywhere in the UK.

Whether you are pulling big lures on sinking lines deep off the dam wall or targeting surface feeders during an evening midge hatch, the quality of the fishing completely matches the views. Between the unreal top water action, the excellent food choices back in Llanidloes, and the sheer scale of the place, Clywedog isn't just another fishery, it's a proper mountain fishing escape. If you appreciate wild settings, hard fighting fish, and a brilliant day out on the water, a day permit here is an absolute no brainer.

Overall 9/10