Fishery guide · Powys
Llyn Clywedog
Llyn Clywedog is a huge, high-altitude reservoir with proper fly-fishing appeal, regular trout stocking and both bank and boat access. A cracking option for anglers after brown, rainbow, blue or tiger trout in a wild Powys setting.
“7.7/10 — A large trout reservoir with wild and stocked fish, seasonal hatches and both bank and boat fishing.”
Tackle Index scorecard
The lowdown
Llyn Clywedog is a 615-acre reservoir on the headwaters of the River Severn, near Llanidloes in Powys. Built in the late 1960s and sitting at over 900 feet above sea level, it’s a big bit of water with a proper upland feel.
- 1 lake: Llyn Clywedog
- Fish: trout
- Tickets from: Full 2026 season permit — £420
- Find it: Llanidloes · SY18 6NX
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Fishery map of Llyn Clywedog
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Around the fishery
A look around the venue
Fishery
Llyn Clywedog
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Which lake suits you?
Based on how each lake is set up — not a ranking.
The full rundown on Llyn Clywedog
Llyn Clywedog is a 615-acre reservoir on the headwaters of the River Severn, near Llanidloes in Powys. Built in the late 1960s and sitting at over 900 feet above sea level, it’s a big bit of water with a proper upland feel.
The fishery is run by Llanidloes and District Angling Association and is primarily a trout fishery. Brown trout are present, including wild fish, while rainbow, blue and tiger trout are reported among the stocked fish. The fishery says around 40,000 fish are stocked into the lake, with trout added weekly from its own trout farm.
Fishing is available from the bank or from boats, but fly fishing is required. That makes this one for anglers who enjoy working a fly rather than reaching for coarse tackle. The reservoir is also used by a sailing club and other water users, so keep your eyes peeled and give everyone plenty of room.
The fishing calendar has some lovely seasonal markers. Spring and autumn buzzer hatches are important food events, while coch-y-bondhu beetles become prominent from about June into July. Autumn daddy-long-legs hatches can provide surface fishing too. Those are the key windows to have in mind when planning a day.
Boat fishing is well catered for, with approximately 35 boats fitted with 4hp petrol motors. The fishery website also describes a fleet of 36 boats, so check the current position when booking. A wheelie boat is available for mobility users, and the boats are available until 30 November.
The fishing lodge is at the boat moorings, with permits available there, plus a tackle and fishery shop, toilets and snacks at the on-site cabin or shop. Boat bookings are handled by telephone. It’s a handy setup for getting sorted before heading onto this broad reservoir.
The 2026 season runs from 12 March to 30 November. The full season permit is £420, while day and evening options give visiting anglers a simpler way in. No night fishing is permitted, and both the correct Environment Agency rod licence and a fishery permit are required. Check the official fishing and boat-rule PDFs before setting off — especially if you’re booking a boat.
Straight from anglers online
Short, unedited extracts from public reviews, credited to the person who posted them. Not checked by us and not a Tackle Index view.
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Llyn Clywedog FAQs
When does the 2026 season run?
The 2026 fishing season runs from 12 March to 30 November.
How much is a 2026 day permit?
The 2026 full-day permit costs £29. Concession full-day permits cost £28 and youth day permits cost £20.
Where can I get permits?
Fishing permits are available from the fishing lodge at the boat moorings. River permits are sold separately from Bradleys Petrol Station in Llanidloes.
How do I book a boat?
Boat bookings are handled by telephone with the fishery.
Where's the nearest tackle shop?
There's tackle and fishery shop on site, so you can grab bits on the day. For anything bigger, stock up before you leave home — or order online in advance.
Do I need to bring food?
There's snacks at the on-site cabin or shop listed, but opening times vary, so pack snacks and plenty of water just in case — especially on a long session.
Are there toilets on site?
Yes — the fishery lists toilets.
Is there parking, and how close is it to the swims?
The fishery doesn't say on what we've checked, so give them a quick call before you set off. Bring a barrow in case it's a walk.
What's the postcode for the sat nav?
SY18 6NX.
How much is a ticket?
Full 2026 season permit: £420; 2026 OAP season permit: £400; 2026 youth-development season permit for ages 12–17: £70; 2026 full-day permit: £29; 2026 concession full-day permit: £28; 2026 youth day permit: £20; 2026 evening permit from 3pm — three-fish limit: £20; Three-day holiday boat package for two anglers: £240; 2026 petrol motor-boat permit: £28; Evening motor-boat permit from 3pm: £20; Single-person weekday boat permit: £22. Prices last checked 2026-10-07 — they can change, so check before you go.
Can I just turn up, or do I need to book?
Day tickets are available on Llyn Clywedog. Busy weekends can fill up, so ring ahead if you've got your heart set on a swim.
What fish are in there?
Across the lakes you'll find trout. See each lake tab for which fish live where.
How many lakes are there?
1 — Llyn Clywedog (615 acres).
Is night fishing allowed?
No — No night fishing is permitted.
Can I bring my dog?
Not covered in the rules we've checked. The fishery doesn't say on what we've checked, so give them a quick call before you set off.
Are bait boats allowed?
It's seasonal — Boats are available until 30 November. The 2026 fishing season runs from 12 March to 30 November.
Do I need barbless hooks?
Most UK fisheries prefer barbless or micro-barbed hooks — ask on arrival if unsure.
Do I need my own unhooking mat or cradle?
Bring one either way — most fisheries expect it and the fish deserve it.
Is it suitable for disabled anglers?
We haven't seen disabled access listed. The fishery doesn't say on what we've checked, so give them a quick call before you set off.
Do I need a rod licence?
Yes — anyone 13 or over fishing in England and Wales needs an Environment Agency rod licence (or Natural Resources Wales in Wales), on top of your fishery ticket.
When's the best time of year to fish here?
Late spring through autumn is prime for most species. Check our live weather edge for this venue before you go — it updates daily.
Anglers' photos
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Day ticket · turn up
Llyn Clywedog: a big welsh reservoir built for fly fishing, with wild and stocked trout plus bank and boat access.
- Size
- 615 acres acres
- Swims
- Not published
- Max anglers
- —
- Species
- trout
Llyn Clywedog is a 615-acre reservoir on the headwaters of the River Severn. It’s primarily a trout fishery, with brown trout present alongside stocked rainbow, blue and tiger trout.
Fly fishing is required, and anglers can fish from the bank or from boats. Spring and autumn buzzers, summer coch-y-bondhu beetles and autumn daddy-long-legs hatches are the main seasonal food events to watch.
The fishery says around 40,000 fish are stocked into the lake, with trout stocked weekly from its own trout farm.
Lake photographs
A look around Llyn Clywedog
Llyn Clywedog
Llyn Clywedog
We’re checking the fishery’s Llyn Clywedog pictures before displaying them here. You can still see the originals on the fishery’s website.
Suits
- Fly anglers who enjoy covering a large reservoir from the bank or a boat.
- Anglers looking for brown, rainbow, blue or tiger trout across a long March-to-November season.
Maybe not for
- Anyone after coarse-fishing methods, night fishing or a quiet waterway without sailing and other water users.
Bait, rigs & seasons
How we'd fish Llyn Clywedog
trout
Fly fishing for the trout
Stocked lake trout cruise and feed up in the water, so you need to find the depth they're at. Start just under the surface and go deeper if nothing's happening.
- A 9ft 6–7 weight rod with a floating line covers most days; carry an intermediate or sinking line for cold or bright spells.
- Early season and cold days: lures like a Cat's Whisker, Blob or Damsel, pulled back in steady strips.
- Warmer days with fish rising: buzzers, Diawl Bachs or a dry fly fished slowly, or static under an indicator.
- Count your fly down (5, 10, 15 seconds) and change depth till you get a pull — then repeat that count.
- Use 6–8lb fluorocarbon tippet, and check the fishery's rules on catch-and-release, bag limits and barbless hooks before you start.
Venue rule: Bag limits and catch-and-release rules vary a lot on trout waters — ask at the lodge before your first cast.
Llyn Clywedog FAQs
What fish are in Llyn Clywedog?
Brown trout, including wild brown trout, are present. Rainbow, blue and tiger trout are reported among the stocked fish.
Can I fish Llyn Clywedog from a boat?
Yes. Boat fishing is available, with approximately 35 boats fitted with 4hp petrol motors. A wheelie boat is available for mobility users.
What's the lake record on Llyn Clywedog?
Going by what the fishery says: The fishery says around 40,000 fish are stocked into the lake, with trout stocked weekly from its own trout farm. That's the owner's figure, not ours — take it as a guide.
How big is Llyn Clywedog and how many swims?
Around 615 acres acres. A big Welsh reservoir built for fly fishing, with wild and stocked trout plus bank and boat access..
Which baits work well on Llyn Clywedog?
We've put together a full bait, rigs and seasons plan for Llyn Clywedog further up this page — it's built from the lake's features and the venue rules. As a rule, match your approach to the stock: with the fish the fishery lists here, a solid food-source boilie and a tidy presentation will catch anywhere on the complex.
When does Llyn Clywedog get busy?
Weekends and bank holidays are busiest, especially spring through autumn. It's a day-ticket lake, so popular swims go early — arrive at first light or midweek if you can.
What weather suits bigger catches on Llyn Clywedog?
A mild south-westerly with falling pressure is the classic carp trigger, and overcast days usually beat bright, still ones. Check our live weather edge for Llyn Clywedog before you go — it ranks every lake here for the next 7 days.
Which pegs are best on Llyn Clywedog?
Honestly, we don't rank pegs — the fish move with wind, pressure and pressure from other anglers. Have a walk and watch the water before you set up; the tips section above has what we've found so far.
Is night fishing allowed on Llyn Clywedog?
No — No night fishing is permitted.
Who does Llyn Clywedog suit?
Good for: Fly anglers who enjoy covering a large reservoir from the bank or a boat.; Anglers looking for brown, rainbow, blue or tiger trout across a long March-to-November season.. Less suited to: Anyone after coarse-fishing methods, night fishing or a quiet waterway without sailing and other water users..
Community reported
Recent angler updates
No angler updates yet — that's normal. Be the first to help the next angler.
How busy was it?
Nobody's said yet. It's part of the 20-second update below.
No live tracking — this is what anglers told us after their session, and it's never part of the venue score.
Water updates from anglers
No active water updates.
Help other anglers
Venue Rule Checker
- Must
Is fly fishing required?
Fishing is fly fishing only.
- Must
Is a fishery permit required?
A fishery permit is required on all waters.
- Must
Is the correct Environment Agency rod licence required?
The correct Environment Agency rod licence is required.
- No
Is night fishing allowed?
No night fishing is permitted.
- No
Can I fish outside the published season?
The close season applies outside the published fishing season.
- Seasonal
Are boats available throughout the fishing season?
Boats are available until 30 November. The 2026 fishing season runs from 12 March to 30 November.
- Yes
Are there other water users on the reservoir?
The reservoir is also used by a sailing club and other water users.
Taken from the fishery’s own pages, last checked 7 October 2026. Rules change — always check with the fishery before you go.
Tips & guides worth reading
How we'd fish each lake
Our own suggestions, worked out from each lake's features, its main fish and the venue rules. They're tried-and-tested methods, not reports from this venue, so watch the water and ask in the tackle shop on the day.
Llyn Clywedog
trout
Fly fishing for the trout
Stocked lake trout cruise and feed up in the water, so you need to find the depth they're at. Start just under the surface and go deeper if nothing's happening.
- A 9ft 6–7 weight rod with a floating line covers most days; carry an intermediate or sinking line for cold or bright spells.
- Early season and cold days: lures like a Cat's Whisker, Blob or Damsel, pulled back in steady strips.
- Warmer days with fish rising: buzzers, Diawl Bachs or a dry fly fished slowly, or static under an indicator.
- Count your fly down (5, 10, 15 seconds) and change depth till you get a pull — then repeat that count.
- Use 6–8lb fluorocarbon tippet, and check the fishery's rules on catch-and-release, bag limits and barbless hooks before you start.
Venue rule: Bag limits and catch-and-release rules vary a lot on trout waters — ask at the lodge before your first cast.
Good background reading. Most of it is a few years old, so treat it as a starting point and ask on the day.
Videos linked by the fishery
What anglers reckon
7.7/10 from Tackle Index: A large trout reservoir with wild and stocked fish, seasonal hatches and both bank and boat fishing.
Straight from anglers online
Short, unedited extracts from public reviews, credited to the person who posted them. Not checked by us and not a Tackle Index view.
We haven’t found any public angler reviews of this venue yet. Fished it? Add yours below.
Our take on the feedback
Our read
Checked Sept '26 — “Llyn Clywedog is a huge, high-altitude reservoir with proper fly-fishing appeal, regular trout stocking and both bank and boat access. A cracking option for anglers after brown, rainbow, blue or tiger trout in a wild Powys setting.”
This is our own summary of recurring public feedback and the venue details we checked, not a copied customer review or a promise you’ll catch. Feedback changes, so we keep it separate from the Tackle Index score.
Angler score
What our readers rate Llyn Clywedog
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