Stillwater · Ordovician Volcanics · Wales / Snowdonia (Nantlle valley, Llyfni catchment)

Llyn Nantlle

Calm mirror-still Llyn Nantlle reflecting snow-capped Snowdonia mountains and a cloudy pink-tinged sunrise sky.

Nantlle sits low in its own valley below the Nantlle Ridge, a proper-sized lake by upland standards and one with a card up its sleeve — a sea trout run that separates it from the club's smaller hill waters.

Fair · Trout
Minkie · 6-10
A respectable few hours, if you choose your moments
Good wave on — drift country. A useful wave. Work the productive shore.
45% confidence
limited data

Llyn Nantlle is often best in spring through autumn.

What moved it
  • WindN 12 km/hGentle breeze
Today's fly
Minkie
Minkie6-10
Retrieve, sub-surface
Conditions on the water
Estimate
Wind
Gentle breeze
N 12 km/h
N
N
from the north
Wave20 cm ripple
Water temp
Air temp12°C
CloudBroken
Pressure1023 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 Trout
When
Browns April–September; sea trout June–August after spates, best after dark
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. Keep a sedge-style dry or emerger on a short leader for the evening rise.
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. Keep a sedge-style dry or emerger on a short leader for the evening rise.

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

Sedge should come on through the afternoon as the water warms.

Bank

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

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
Heather FlyHatch
2
2
Daddy Long LegsHatch
2
3
2
Claret DunHatch
2
3
2
Murrough (Great Red Sedge)Hatch
2
3
2

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

Ranked for today
Trout fly box
Bays & launches · 1
Day ticket via Seiont, Gwyrfai and Llyfni Fishing SocietyAccess varies
Valley lake below the Nantlle Ridge with wild browns and a genuine sea trout run — arguably the pick of the society's smaller waters.
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What's coming
Plan ahead
5-day outlook
Condition match
65%
Cloud70%
Wind65%
Temp60%

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

Other water nearby · 5
Gallery · 2
  1. Calm mirror-still Llyn Nantlle reflecting snow-capped Snowdonia mountains and a cloudy pink-tinged sunrise sky.
    Nantlle lake Sunrise
  2. Terrain map of the venue
    Terrain map
About this water

Nantlle sits low in its own valley below the Nantlle Ridge, a proper-sized lake by upland standards and one with a card up its sleeve — a sea trout run that separates it from the club's smaller hill waters. The wild browns fish well enough on their own terms, but it's the sewin that give Nantlle its edge, arriving with the summer spates and giving the lake a different character after dark than it has by day. It's part of the Seiont, Gwyrfai and Llyfni Fishing Society's wider portfolio, alongside Cwellyn, Padarn, Dywarchen and Cwm Silyn, and it holds its own against waters with bigger reputations. Worth timing a visit around water levels if the sea trout are the target.

  • Lake
  • Ordovician volcanics
Why this score
  • Daddy Longlegs are in their seasonal window, boosting the chance of targeted feeding.
Directions
Seasons & zones

Sea trout: Variable seasonal (2026)

Related guides
Casting instructors near here
Booking & contacts