Spate · Granite · Co. Down / Mourne Mountains, GB-NIR

River Shimna

The Shimna River running through autumn woodland in Tollymore Forest Park in the Mourne Mountains, County Down, Northern Ireland.

The Shimna is a beautiful mountain spate river flowing from the Mourne Mountains through Tollymore Forest Park to the sea at Newcastle.

Today · Closed season
Stonefly Nymph
Forecast · Today
Closed season
Out of season. File this water for the right month.
40% projected
Today's fly
Stonefly Nymph
Stonefly Nymph
Conditions on the water · Today
Live gauge
Level
Rising
0.09 m
Lifting fast
Water temp8.7°C
ClarityUnfishable
Weather9°C
WindN 32 km/h
Pressure1009 hPa
Rain · recent0.0 mm
Rain · ahead3.5 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
9°C est.ideal 10–16°C
0°14°28°
How to fish it · for Atlantic Salmon
When
Morning into early afternoon.
Where
Pool tails, steadier runs, and any water with pace.
Method
Fish a sensible line-and-fly combination for the height and pace of water.
Kit
13 ft #8/9 double-hander in spate, 10 ft #8 single in low water. Floating line plus a fast-sink tip. 12–15 lb fluoro tippet.
Likely species
Stoneflies
Gammarids
Hatch timeline · todayPeak at 11am

12pm(now) — Autumn Needle Fly

Stage: Creeping nymphsApproach: Heavy nymphActivity: 36%
Also:Autumn Olive22%
Peak emergence window

Peak activity at 11am — Autumn Needle Fly (Autumn Needle Fly, Peak emergence window)

Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds as a supporter.

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Beyond the hatch · worth watchingambient prey(1)

Hatch predictions

Supporters see what else is on the menu.

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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
March BrownHatch
2
3
2
CapererHatch
2
3
3
2
Heather FlyHatch
2
2
Autumn DunHatch
2
3
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.

What's coming
Plan ahead
5-day outlook
Other water nearby · 5
River Lagan — Shaw's Bridge
38 km
0
Brown trout · Salmon
River Lagan
18 km
Brown trout
Ballymascanlan River
37 km
Brown trout · Sea trout
River Cusher
37 km
Brown trout
Castletown River
40 km
Brown trout · Sea trout
Gallery · 2
  1. The Shimna River running through autumn woodland in Tollymore Forest Park in the Mourne Mountains, County Down, Northern Ireland.
    The Shimna River flowing through autumn woodland in Tollymore Forest Park, County Down.
  2. Terrain map of the venue
    Terrain map
About this water

Clear granite water, fast-draining — rises within hours and drops just as fast. Sea trout from June are the main draw, with small runs of salmon from May. Brown trout are plentiful but small. The Shimna Angling Club manages access. The forest park setting makes this one of the most scenic rivers in Northern Ireland. Fish on the drop after rain — low water means it runs almost dry in summer. Atlantic salmon are managed under DAERA and Loughs Agency conservation byelaws, with mandatory catch-and-release on many waters; check current rules before fishing.

Hatches & food

No venue-specific hatch data yet; as a Mourne upland spate river, expect the sparse, flood-driven mix of stoneflies, small upwings and terrestrials typical of these freestone streams — a general expectation, not an observed hatch.

Sea trout here

Summer-autumn runs, seasonal patterns vary by region

  • Granite
The full read · show the working · for Atlantic Salmon · confidence 75%
How the river scores — hydrology factors
Water heightMedium Ideal0.0
Recent riseNone0.0
Falling after liftNot Applicable0.0
Water temperatureCool To Moderate0.0
Time in seasonOpening Period0.0
ClarityClearing0.0
Hydrology base0.0
Legal gate: Unknown Check Local Rules
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Salmon 1 March → 31 October

Sea trout: Variable seasonal (2026)

Related guides
Atlantic Salmonsalmon tacticsIrish Salmon Rivers Guidefive great salmon fisheriesConnemaraIrish fishing
Casting instructors near here
Booking & contacts
At a glance

River Shimna is a spate river in Co. Down / Mourne Mountains, Northern Ireland. Its recorded elevation is about 8 m above sea level and the catchment geology is granite. The river is described as roughly 12 km long. Our data lists brown trout, salmon and sea trout here. It is classed as a salmon river. The salmon season is recorded as running from 1 March to 31 October. Best window recorded for anglers: June–September (sea trout), May–July (salmon). Core methods listed: upstream nymph and dry fly (trout); across and down wet fly (sea trout); small doubles for salmon. Level and flow data for this water is linked from 1 gauge. Nearby waters in our listings include River Lagan at 18 km, Ballymascanlan River at 37 km and River Cusher at 37 km.