Spate · Mixed · Gipuzkoa, País Vasco

Bidasoa

A river weir in the foreground with a Basque village of white houses and a church tower on the far bank, backed by wooded hills

A transnational border river between Spain and France, draining the western Pyrenees with classic mixed-geology spate character.

Tomorrow · Not the day for it
Czech Nymph
Forecast · Tomorrow
Not the day for it
Not much stacked in your favour today. Worth an hour if you are nearby, not worth the special trip.
45% projected
Today's fly
Czech Nymph
Czech Nymph
Conditions on the water · Tomorrow
Live gauge
Level
Rising
0.91 m
Lifting fast
Water temp11.2°C
ClarityUnfishable
Weather13°C
WindN 18 km/h
Pressure1011 hPa
Rain · recent19.4 mm
Rain · ahead10.2 mm

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

Water temperature for Brown Trout
Ideal
11°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.
Why this works
Excellent — water temperature is right today, though insect activity could be better.
Likely species
Stoneflies
Gammarids
Hatch timeline · tomorrowPeak at 11am

12pm(now) — Autumn Needle Fly

Stage: Creeping nymphsApproach: Heavy nymphActivity: 30%
Also:Autumn Olive21%
Peak emergence window4 food groups active

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 4 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
Sea trout runRun
1
2
1
Trout seasonSeason
1
2
2
2
1
March BrownHatch
2
3
2
Late March BrownHatch
2
3
2
Large Brook DunHatch
2
3
2
Large StoneflyHatch
2
3
2

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.
  • Gipuzkoa fishing licence required
  • Bidasoa border-water rules, named beats, and any cross-border coordination matter more than old salmon-era assumptions, so check the exact section before travel.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Bidasoa tributaries (Navarra side)
10 km
0
Brown trout · Sea trout
Urumea
23 km
30
Brown trout · Sea trout
Río Ulzama
24 km
0
Brown trout
Nive
28 km
0
Brown trout · Salmon · Sea trout
Oria
30 km
71
Brown trout · Sea trout
Gallery · 2
  1. A river weir in the foreground with a Basque village of white houses and a church tower on the far bank, backed by wooded hills
    The Bidasoa river flowing past the village of Sunbilla, Gipuzkoa, in the evening light
  2. Terrain map of the venue
    Terrain map
About this water

In modern practical fly-fishing terms, the Bidasoa should be treated as a trout-and-sea-trout river with strong heritage-salmon identity rather than as a realistic salmon-chasing destination. The 5-hour response time to rainfall still creates excellent post-spate windows, and the lower and middle sections around Bera remain the key structured water.

Hatches & food

In the steep, often pressured Atlantic rivers of the Basque Country, trout opportunities centre on spring olives and other up-wings when flows and colour briefly line up, with caddis and buzzers helping to sustain sport into early and mid-summer, and terrestrials from grassy, wooded margins adding surface food in quieter, recovering reaches.

  • Mixed
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · ES017MSPFES010MAR002420

The full read · show the working · for Brown Trout · confidence 90%
How the 80 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity75 × 18%13.5
Feeding Time70 × 13%9.1
Pressure80 × 7%5.6
Insect activity55 × 12%6.6
Conditions total= 80
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Sea trout 1 May → 31 July
  • Trout third Sunday of March → 31 July

Sea trout: Variable seasonal (2026)

Salmon: Heritage only (2026) — Heritage salmon river. In practical angling terms, salmon are not a target species — focus on trout and sea trout.

Related guides
Pyrenees PlaybookSpanish riversEuro Nymphingsubsurface methods
Booking & contacts
At a glance

Bidasoa is a spate river in Gipuzkoa, País Vasco, Spain. It sits at about 102 m above sea level. The river is described as roughly 69 km long. Species listed for this water: brown trout and sea trout. The trout season is recorded as running from third Sunday of March to 31 July. The sea trout season is recorded as running from 1 May to 31 July. Best window recorded for anglers: March–July for trout, with sea trout adding interest later in the legal season. Core methods listed: dry fly; wet fly; euro nymphing. Level and flow data for this water is linked from 4 gauges. Its Water Framework Directive ecological status is recorded as good. Nearby waters in our listings include Bidasoa tributaries (Navarra side) at 10 km, Urumea at 23 km and Río Ulzama at 24 km.