Limestone · West / Mayo, IE

Lough Conn / Lough Cullin

Lough Conn, County Mayo — wide open lough viewed from Pontoon bridge, calm water and distant shoreline

Twin loughs joined by a short channel at Pontoon, and different water in every way that matters.

Today · Closed season
Perch Fry
Forecast · Today
Closed season
Out of season. File this water for the right month.
40% projected
Today's fly
Perch Fry
Perch Fry
Conditions on the water · Today
Live gauge
Level
Rising
1.56 m
Lifting fast
Water temp9.6°C
ClarityVery coloured
Weather7°C
WindN 26 km/h
Pressure1005 hPa
Rain · recent0.2 mm
Rain · ahead1.9 mm

The nearest gauge doesn't record temperatures, so we've estimated it — defer to the river keeper's advice.

Water temperature for Atlantic Salmon
Cool — slow
10°C est.ideal 10–16°C
0°14°28°
How to fish it · for Atlantic Salmon
When
Salmon run through from the Moy system in May and June. Conn is not a destination salmon water — these are fish moving upstream. Fish dropping water after a lift.
Where
The Pontoon channel and the lower lough where salmon enter from the Moy. Don't fish the open lough for salmon — they're moving, not holding.
Method
Drift fly with team wets if you're trout fishing and a salmon comes through; otherwise this is not where to spend the week. Murrough on the bob is a known salmon take in mayfly season.
Kit
10 ft #7, intermediate plus floater, 12 lb fluoro. The trout-water rod plus heavier tippet — you're not gearing up for salmon-only here.
Likely species
Stoneflies
Chironomids
Gammarids
Hatch timeline · todayPeak at 10am

12pm(now) — Black Midge

Stage: On emergersApproach: Emerger or dryActivity: 22%

Peak activity at 10am — Black Midge

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Top prey shown — see all 4 as a supporter.

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Evidence
Survey-backed · regionalHigh confidence

Backed by regional invertebrate surveys; no sampling on this exact reach yet.

Through the year
0–3 scale · November highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Salmon runRun
1
2
2
2
2
2
2
1
Trout seasonSeason
1
2
2
2
2
2
2
1
Green PeterHatch
2
3
2
Murrough (Great Red Sedge)Hatch
2
3
2
DuckflyHatch
2
2
Mayfly (Green Drake)Hatch
2
2

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

Ranked for today
Atlantic Salmon fly box

Connemara/Mayo low water: a lightly-dressed shrimp on a floating line with sink tip, sized down from 8s in cold spring water to 12s and 14s as summer water warms and clears. Where the current runs faster, a slim tube or hairwing swung through tracks better than a shrimp.

Permits & access
Free state water
State rod licence required for trout / salmon as applicable.
  • No permit needed — state rod licence only
  • Boats from Crossmolina, Pontoon, Foxford
  • Salmon licence additional.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Moy
16 km
0
Brown trout · Salmon · Sea trout
Lough Conn / Lough Cullin
< 1 km
Brown trout · Salmon
Lough Conn / Lough Cullin
< 1 km
Brown trout · Salmon
Lough Conn / Lough Cullin
< 1 km
Brown trout · Salmon
Lough Conn / Lough Cullin
< 1 km
Brown trout · Salmon
Gallery · 8
  1. Lough Conn, County Mayo — wide open lough viewed from Pontoon bridge, calm water and distant shoreline
    Lough Conn
  2. Photo of Lough Cullin
    Lough Cullin
  3. Wide panoramic view north across Lough Conn from Pontoon Bridge, County Mayo.
    Lough Conn from Pontoon Bridge
  4. Open water of Lough Conn viewed from the R310 Pontoon bridge.
    Lough Conn from the Pontoon Bridge
  5. Lough Conn, County Mayo, an open lough landscape.
    Lough Conn
  6. The Pontoon crossing between Lough Conn and Lough Cullin, open water on both sides.
    Pontoon, Lough Conn / Lough Cullin
  7. Lough Cullin viewed from the R310, the sister lough to Lough Conn at Pontoon.
    Lough Cullin from the R310
  8. Terrain map of the venue
    Terrain map
About this water

Conn is limestone-fed, clear, and quick to respond, with mayfly and olive hatches as good as Mayo offers; Cullin runs darker and peatier, a different mood entirely for water lying so close. Together they hold the best brown trout fishing the county has, and salmon run through from the Moy system besides. Dapping earns its keep whenever the breeze sets fair.

Hatches & food

Named among the western limestone loughs for duckfly from around 17 March for about three weeks, lake olives from late April to early May, and a mayfly period from after the first week of May into early June, with Caenis at first light and sedges late in the evening through summer - though this is regional guidance, not a measured hatch on Conn itself. Lough Cullin specifically is reported to fish well on duckfly and mayfly from late March through June, before summer weed growth curtails the sport.

  • Lough system
  • Limestone
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown
What this classification means

WFD code normalized 2026-06-18: IE_WE_34_406b → IEWE_34_406B (EPA national format → EEA WISE euSurfaceWaterBodyCode; same water body, now joinable to WISE). Status confirmed against EEA WISE 2022 (3rd RBMP). Source: discodata.eea.europa.eu. | Prior note: EPA WFD 2019-2024 (lake layer) — Lough Conn: Good ecological status. Re-tagged 2026-06-18 from IEWE_34C050100 (a river/stream water body, not the lough) to the lough's own EPA lake water body. Source: EPA Ireland WFD 2019-2024 classification (catchments.ie / EDEN).

EPA (Ireland) · IEWE_34_406B

Directions
Apple MapsGoogle Maps
Seasons & zones
  • Salmon 1 February → 30 September
  • Trout 15 February → 30 September

Sea trout: Variable seasonal (2026) — Conn (Mayo) carries sea-trout relevance but should not be modelled as a clean "primary open" signal — returns are condition-dependent and stock context tracks the wider western Irish picture.

Related guides
Irish Loughs Playbooklough-style fishingThermal Layers & Troutreading depth and temperatureAtlantic Salmonsalmon tactics
Casting instructors near here
Booking & contacts
Clubs & associations
  • Lough Conn & Cullin AA
    Primary club for this water · Members only: no day tickets, join the club to fish here · Lough Conn and Cullin Anglers Association · General trout fishing context on western loughs is often free/public; association membership is a separate club layer.
At a glance

Lough Conn / Lough Cullin is a limestone river in West / Mayo, Ireland. Its recorded elevation is about 171 m above sea level and the catchment geology is limestone. The river is described as roughly 16 km long. Our data lists brown trout and salmon here. It is classed as a salmon river. The trout season is recorded as running from 15 February to 30 September. The salmon season is recorded as running from 1 February to 30 September. Best window recorded for anglers: March–September; mayfly mid-May to mid-June; excellent early-season buzzer fishing. Core methods listed: loch-style wet fly drift from boat; dry fly during mayfly; trolling for salmon (traditional). Level and flow data for this water is linked from 1 gauge. Its Water Framework Directive ecological status is recorded as good. Access is recorded as a lough where no permit is required. Boat fishing is recorded as available. Nearby waters in our listings include Lough Conn / Lough Cullin at < 1 km, Lough Conn / Lough Cullin at < 1 km and Lough Conn / Lough Cullin at < 1 km.