Upland Natural Lake · Slate · Gwynedd / Snowdonia

Llynnau Mymbyr

Panoramic view across the twin lakes of Llynnau Mymbyr toward Moel Siabod and Snowdon in Eryri National Park, Wales

Twin llyns in the Nant Gwynant valley below Snowdon.

Fair · Trout
Diawl Bach · 12-14
Fairlive now
Good drifting conditions on Llynnau Mymbyr
Water temperature is the limiting factor today, not the wave. Fish dawn or dusk if you go at all, and handle everything with extra care.
53% confidence
What moved it
  • WindSW 9 km/hLight breeze
Today's fly
Diawl Bach
Diawl Bach12-14
Washing-line, sub-surface
Conditions on the water
Live gauge
Wind
Light breeze
SW 9 km/h
N
SW
from the south-west
WaveRipple
Water temp—
Air temp23°C
CloudBroken
Pressure1021 hPa
Rain · recent0.0 mm

Some readings unavailable — check directly before fishing.

How to fish it · for Trout
When
May to September
Where
Set up a broadside drift and cover the water systematically. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point.
The plan
Plan A

Set up a broadside drift and cover the water systematically. Work a bushy searching pattern on the bob and drop a contrasting nymph on the point.

Plan B

If the main plan is not working, switch to a smaller, more imitative pattern fished slower and deeper. A change of drift angle can also make a difference.

Watch for

Buzzers may strengthen through the middle of the day as conditions warm.

Bank

Bank-only venue. Fish from accessible margins, points, weed edges, and inflows.

Sub-surface · on the nymphunder the surface

Hatch predictions

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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
Trout seasonSeason
1
2
2
2
2
2
1
Daddy Long LegsHatch
2
3
2
Murrough (Great Red Sedge)Hatch
2
3
2
Black MidgeHatch
2
3
3
3
3
3
3
3
3
3
3
2
Lake OliveHatch
1
2
2
2
2
2
1

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

Ranked for today
Trout 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.

What's coming
Plan ahead
5-day outlook
Condition match
88%
Cloud100%
Wind100%
Temp60%

Conditions are ideal for Llynnau Mymbyr — wind, cloud and temperature all line up.

Other water nearby · 5
Llyn Diwaunedd
3.0 km
Brown trout · Arctic char
Llyn Bochlwyd
4.0 km
Brown trout
Llyn Idwal
5.0 km
Brown trout
Llyn Ogwen
5.0 km
Brown trout · Rainbow trout
Ffynnon Lloer
6.0 km
Brown trout
Gallery · 2
  1. Panoramic view across the twin lakes of Llynnau Mymbyr toward Moel Siabod and Snowdon in Eryri National Park, Wales
    Llynnau Mymbyr looking toward Moel Siabod and Snowdon, Eryri
  2. Terrain map of the venue
    Terrain map
About this water

Twin llyns in the Nant Gwynant valley below Snowdon. Wild brown trout with dramatic mountain backdrop — perhaps Wales's most photographed fishing location. Capel Curig area. Small wild trout respond to traditional wet flies, dabblers and terrestrials. Day tickets from Plas y Brenin.

  • Lake
  • Slate
Why this score
  • Wind conditions (ripple) closely match what this water fishes best in.
  • Cloud cover (mixed) suits the fishery well.
  • Buzzers are in their seasonal window, boosting the chance of targeted feeding.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 3 March → 30 September
Related guides
Scotland Playbookloch & river fishingThermal Layers & Troutreading depth and temperatureEuro Nymphingsubsurface methods
Casting instructors near here
Booking & contacts
Clubs & associations