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
Contributor photo

The Bidasoa river flowing past the village of Sunbilla, Gipuzkoa, in the evening light

Ksarasola

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

Poor · Brown Trout
Klinkhammer · 14-18
Poorlive now
Not the day for it
River temperature is the limiting factor today, not the flow. This is not the day to push it. Check the thermal advice above before you head out.
80% confidence
What moved it
  • Level1.03 mRising in the last 6h
  • Water temp21.2°C
  • ClarityClear
Today’s fly
Klinkhammer
Klinkhammer14-18
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
1.03 m
lowspate
Water temp21.2°C
ClarityClear
Weather21°C
WindSW 11 km/h
Pressure1018 hPa
Rain · recent0.0 mm
Rain · ahead1.9 mm

Live readings — water temperature is an estimate where the gauge does not record it.

Water temperature for brown trout
Warm — slow
21°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
⚠️ Water at 21.2°C — above the brown trout caution line (18°C). Fish dawn or dusk only. Land it fast, wet hands, no air shots. Otherwise poor — water clarity is in the right range.
Sub-surface · on the nymphunder the surface

Hatch predictions

See the full sub-surface read with Pro.

Start free trial

14-day free trial. Cancel anytime.

Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

Start free trial

14-day free trial. Cancel anytime.

Evidence
Records-basedModerate confidence

Based on species-occurrence records, not local invertebrate surveys.

Through the year
0–3 scale · July 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
GrannomHatch
2
2
Large StoneflyHatch
2
3
2
Yellow SallyHatch
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
Water here around 21°C. Nothing cooler within range — carry a thermometer.
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

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

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

WFD classification · ES017MSPFES010MAR002420

The full read · show the working · for brown trout · confidence 80%
How the 20 is built — score × weight = contribution
Temperature12 × 28%3.4
Flow40 × 22%8.8
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity34 × 12%4.1
Limiting factor: Water temperature (21.2°C) is outside Brown Trout's preferred range (10–16°C)= 45
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
Cooler water — back toward the 10–16 °C ideal band — would lift the score and ease welfare.
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Sea trout1 May → 31 July
  • Troutthird 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