Stillwater · Mixed · Pembrokeshire, South West Wales (Preseli Mountains)

Llys y Fran Reservoir

A lone angler sits on the bank of Llys y Fran Reservoir fishing, with calm blue water stretching to the dam and green Pembrokeshire countryside beyond.

Pembrokeshire's principal reservoir and one of South Wales's better-known stillwater trout fisheries — a 212-acre working drinking-water reservoir on the Preseli Mountains' southern slopes, dammed across the River Syfynwy in 1972 and run directly by Welsh Water as a proper, well-organised fishery rather than a concession.

Good · Rainbow
Diawl Bach · 12-14
Goodlive now
Good summer conditions for Llys y Fran Reservoir
Good wave on — drift country. Drift fishing weather — three flies on a long leader.
70% confidence

Llys y Fran Reservoir is often best in spring through autumn.

What moved it
  • WindN 19 km/hGentle breeze
Today's fly
Diawl Bach
Diawl Bach12-14
Washing-line, sub-surface
Conditions on the water
Estimate
Wind
Gentle breeze
N 19 km/h
N
N
from the north
Wave40 cm chop
Water temp—
Air temp17°C
CloudClear
Pressure1025 hPa
Rain · recent0.0 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

How to fish it · for Rainbow
When
Conditions are not ideal but fishable at Llys y Fran Reservoir. The ripple should help fish move and feed more confidently.
Where
Start with Diawl Bach (12-14) — on the bob / top dropper — slow figure-of-eight retrieve. Evening can produce explosive surface takes — try a foam beetle or booby on a long leader. Rainbows respond to more active retrieves — try short strips between pauses.
The plan
Plan A

Start with Diawl Bach (12-14) — on the bob / top dropper — slow figure-of-eight retrieve. Evening can produce explosive surface takes — try a foam beetle or booby on a long leader. Rainbows respond to more active retrieves — try short strips between pauses.

Plan B

Fish early and late, try deeper during the heat of the day with a fast-sinking line.

Watch for

Evening tends to be the best period in summer — stay late if you can for a sedge or spinner fall.

Either bank or boat

Good ripple suits both bank and boat. Bank: work inflows, dam walls, and points. Boat: broadside drift covering wind lanes.

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 5 with Pro.

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Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Reservoir BuzzerHatch
2
3
3
3
3
3
2
Daphnia SwarmHatch
2
3
3
3
2
Lake OliveHatch
2
3
3
3
3
3
2
Silverhorns & LonghornsHatch
1
2
2
2
1

Numbers are intensity 0 (none) to 3 (peak) — a guide, not a guarantee.

Ranked for today
Rainbow fly box

More straightforward stocked-water behaviour than the upland competition reservoirs, with stronger early-season lure and booby bias but still good natural-fly periods.

Bays & launches · 1

Run and booked directly by Welsh Water — the most straightforwardly bookable of the Tier 3 stillwaters.

Llys y Fran — Welsh Water day tickets & boat hireDay tickets
8-hour bank sessions with 2/4/6-fish bag options, or electric boat hire (fly only) by the half or full day.
Visit official site ↗
What's coming
Plan ahead
5-day outlook
Condition match
64%
Cloud25%
Wind65%
Temp100%

A reasonable day here, though cloud isn't quite in the sweet spot.

Other water nearby · 1
Garnffrwd Park
48 km
Brown trout
Gallery · 2
  1. A lone angler sits on the bank of Llys y Fran Reservoir fishing, with calm blue water stretching to the dam and green Pembrokeshire countryside beyond.
    Angling above Llys-y-frân dam
  2. Terrain map of the venue
    Terrain map
About this water

Pembrokeshire's principal reservoir and one of South Wales's better-known stillwater trout fisheries — a 212-acre working drinking-water reservoir on the Preseli Mountains' southern slopes, dammed across the River Syfynwy in 1972 and run directly by Welsh Water as a proper, well-organised fishery rather than a concession. Regularly stocked rainbow trout carry the fishery, backed by a resident head of wild brown trout, fished from the bank or from electric-powered hire boats (fly only from the boats). It's genuinely a working water-supply asset first — Welsh Water suspended fishing here for a stretch in 2024 when a dry spell exposed the banks and forced the launch pontoon to move, which is worth knowing before you plan a trip in a drought year, even though bookings have run normally since.

  • Reservoir
  • Mixed
Why this score
  • Temperature (cool) is in the sweet spot for summer fishing.
  • Daddy Longlegs are in their seasonal window, boosting the chance of targeted feeding.
Related guides
Big Stillwater Playbookreservoir tacticsReservoir Entomologymatching the hatchThermal Layers & Troutreading depth and temperature
Casting instructors near here
Booking & contacts