Large River · Volcanic · South Iceland

Þjórsá

A fly angler stands on volcanic rocks casting into the wide, powerful rapids of the Thjorsa river in Iceland, with green hills in the background.

Iceland's longest river.

Prime · Atlantic Salmon
Sunray Shadow · tube 3 6cm
Primelive now
Prime conditions — go now
Low and clear — careful approach country. Cover the water properly, fish each lie once.
85% confidence
What moved it
  • LevelLight rain recentlyNo gauge reading
  • Water temp13.9°C
  • ClarityClear
Today's fly
Sunray Shadow
Sunray Shadowtube 3 6cm
Long-water tubes carry well across the broad Þjórsá glides. Strip-back is the trigger when fish follow.
Conditions on the water
Estimate
Level
Light rain recently
No gauge reading
Water temp13.9°C
ClarityClear
Weather13°C
WindNW 15 km/h
Pressure1005 hPa
Rain · recent9.1 mm
Rain · ahead3.7 mm

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

Water temperature for Atlantic Salmon
Ideal
14°C est.ideal 1014°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.
Why this works
Excellent — water temperature is right today, though river flow could be better.
Hatch timeline · todayQuiet day

Hatch predictions

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Sub-surface · on the nymphunder the surface

Hatch predictions

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Beyond the hatch · worth watchingambient prey

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Evidence
ModelledModerate confidence

Modelled from regional ecology — no survey or occurrence data for this water yet.

Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
1

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

Ranked for today
Atlantic Salmon fly box
Permits & access
Permit required — see local rules.
  • Major nationwide salmon river
  • Permits via local operators and clubs
  • Some beats less pressured than famous rivers.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Gallery · 3
  1. A fly angler stands on volcanic rocks casting into the wide, powerful rapids of the Thjorsa river in Iceland, with green hills in the background.
    Salmon Fishing on the River Thjorsa, Iceland
  2. Photo of Þjórsá
    Þjórsá
  3. Terrain map of the venue
    Terrain map
About this water

Iceland's longest river. Major salmon and trout drainage with extensive productive water. Less intensive commercial operation than premium named rivers but excellent fishing opportunity. Volcanic bedrock underlies this river. Iceland's salmon are managed conservatively under operator and national rules — quotas, size limits and catch-and-release are widely applied; check the river's rules before fishing.

Under the surface

Þjórsá is the longest river in Iceland — some two hundred and thirty kilometres from the Hofsjökull ice down across the southern lowland to the sea, draining a basin of more than seven thousand square kilometres with its great tributary the Tungná. It is a true glacial river, grey and opaque with meltwater, tracking for much of its lower course the edge of the Great Þjórsá Lava, the largest single lava flow on Earth since the last ice age, laid down some 8,600 years ago. Despite the murk it carries one of the largest wild salmon stocks in the country — unusually, fish that spawn and grow in glacial water, a rarity worldwide — most of them pushing through past Urriðafoss in June. This is big, powerful, silt-laden water on a broad gradient. Wading is bold work in poor visibility; read the lava-edged channel rather than the bottom.

Wading: Poor visibility in silt laden glacial water

  • River
  • Volcanic
  • Unconfined
  • Large river
Why this score · for Atlantic Salmon
  • Temperature10030% weight
  • Flow6025% weight
  • Clarity9520% weight
  • Feeding Time8515% weight
  • Pressure8510% weight
Related guides
Booking & contacts
Permits & access