Freestone · Limestone · Navarra, ES

Río Erro

Río Erro venue image

A pristine Irati tributary in the eastern Pyrenean sector of Navarra, flowing through a compact limestone catchment with high elevation and steep gradients.

Poor · Brown Trout
Pheasant Tail Nymph · 14–18
Closed season
Out of season. Try elsewhere.
Closed — confidence not applicable today.
What moved it
  • LevelProxyvia Río Irati
  • Water temp10.4°C
  • ClarityClear
Today's fly
Pheasant Tail Nymph
Pheasant Tail Nymph14–18
High-confidence seasonal pick
Conditions on the water
Proxy gauge
Level
Steady
Proxy
via Río Irati
Water temp10.4°C
ClarityClear
Weather8°C
WindS 13 km/h
Pressure1012 hPa
Rain · recent15.7 mm
Rain · ahead15.4 mm

No gauge on this water — conditions are inferred from Río Irati. The trend transfers, the absolute level does not.

Water temperature for Brown Trout
Ideal
10°C est.ideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Nymphing can work through most of the day.
Where
Cover mixed depths.
Method
Start with tight-line nymphs and adjust if fish rise or drift higher.
Kit
9 ft #4 rod, floating line, 12 ft tapered leader to 4–5 lb fluoro tippet.
Likely species
Stoneflies
Gammarids
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 5 active hatches hour by hour as a supporter.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 3 guilds 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
Trout seasonSeason
1
1
Daddy Long LegsHatch
2
3
3
2
Evening SedgeHatch
2
3
3
3
2
Large Dark OliveHatch
1
2
2
1
Iron BlueHatch
1
2
2
2
2
2
2
1

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

Ranked for today
Brown Trout fly box
Permits & access
Permit required — see local rules.
  • Gobierno de Navarra fishing licence required
  • Check the exact tramo and any daily-permit or coto-pass requirement for the named stretch before travel.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Río Urrobi
9.0 km
0
Brown trout
Río Irati
12 km
0
Brown trout
Río Ulzama
20 km
0
Brown trout
Río Areta
23 km
0
Brown trout
Bidasoa tributaries (Navarra side)
23 km
0
Brown trout · Sea trout
Gallery · 1
  1. Terrain map of the venue
    Terrain map
About this water

Clear, cold alpine freestone with pocket water and short pools holding small to medium wild browns. Technical nymphing and dry fly essential — delicate presentation and careful wading. Limestone geology means rapid snowmelt rise and a fast return to base flow.

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

WFD ecological status High → Good corrected to EEA WISE 2022 (3rd RBMP) classification for waterbody ES091MSPF698 (was a stale earlier-cycle value). Source: EEA WISE SWB_SurfaceWaterBody (discodata.eea.europa.eu), verified 2026-06-18.

WFD classification · ES091MSPF698

The full read · show the working · for Brown Trout · confidence 75%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow40 × 22%8.8
Clarity95 × 18%17.1
Feeding Time80 × 13%10.4
Pressure80 × 7%5.6
Insect activity32 × 12%3.8
Conditions total= 74
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowproxy via Río Iratiproxy
Prey activitysurvey-backed invertebrate datasurvey
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 May → 30 June

    RSS Irati–Erro basin (2,728 permits in 2026). All catch-and-release. Extendable to 15 Jul by resolution. Daily basin permit required.

Related guides
Fly Fishing Near Pamplonafeatured in this guidePyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Río Erro is a freestone river in Navarra, Spain. Its recorded elevation is about 818 m above sea level and the catchment geology is limestone. The river is described as roughly 30 km long. The species listed for this water is brown trout. The trout season is recorded as running from 1 May to 30 June. Best window recorded for anglers: Spring into early summer within the current Navarra tramo calendar. Core methods listed: dry fly; euro nymphing; small wet fly. Level and flow data for this water is linked from 2 gauges. Its Water Framework Directive ecological status is recorded as good. Nearby waters in our listings include Río Urrobi at 9.0 km, Río Irati at 12 km and Río Ulzama at 20 km.