Freestone · Limestone · Primorska, SI

Idrijca

The Idrijca river near Most na Soči, Slovenia, with clear green water.
Prime · Brown Trout
Streamer / Woolly Bugger · 6-10
Temporary closure · troutReported 31 Jul 2026

Total fishing suspension in force (low water / high temperature)

RD Idrija had a total suspension of fishing in force as of 31 July 2026 for low water and high water temperature, alongside a national low-water welfare warning live on ribiskekarte.si. This is a biophysical do-not-fish state, not a routine seasonal closure — check RD Idrija's current notice before travelling.

RD Idrija club announcements ↗

Temporary notices from official orders and recent fishery reports — they clear automatically once out of date. Always confirm locally before travelling.

Primelive now
About as good as it gets
River high but settled. Coloured water — fish bigger and deeper, confident takes down the seams.
90% confidence
What moved it
  • Level70.00 m
  • Water temp10.8°C
  • ClarityClear
Today's fly
SW
Streamer / Woolly Bugger6-10
High-confidence seasonal pick
Conditions on the water
Live gauge
Level
Steady
70.00 m
Water temp10.8°C
ClarityClear
Weather20°C
WindN 3 km/h
Pressure1016 hPa
Rain · recent0.0 mm
Rain · ahead13.4 mm

Live readings only. Trends shown where the gauge supports them.

Water temperature for Brown Trout
Ideal
10.8°Cideal 10–16°C
0°14°28°
How to fish it · for Brown Trout
When
Olives off through spring afternoons, sedge into evening. Cold limestone water needs the air warm before fish move — wait for midday in March, hatch-time later in summer.
Where
Pool-riffle pockets through the middle valley below Idrija. Bedrock-gorge runs in the upper river; pool tails and the cushion behind boulder seams.
Method
Upstream nymph through the broken water, dry to risers in the glides. The water's emerald-clear — long leader, fine tippet, careful wading. Slovenian rivers reward precision.
Kit
9 ft #4 — medium freestone with limestone clarity. Floating line, 12 ft leader to 4 lb fluoro. Polished carbonate is slick — felt or studded soles.
Why this works
Excellent — water temperature is right today, though insect activity could be better.
Likely species
Mayflies
  • Blue-winged oliveMost likely
    #16–18 · Dun
    Duns are up; a sherry spinner fall may follow.
  • Anglers curse mayfliesAlso possibleLower confidence
    #20–22 · Spinner
    Go tiny: 20-22 spent spinner, single fly, long tippet.
Hatch timeline · todayQuiet day

Hatch predictions

Today's headline hatch shown — see all 12 active hatches hour by hour with Pro.

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Sub-surface · on the nymphunder the surface

Hatch predictions

Top nymph shown — see all 4 guilds with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 2 with Pro.

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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
Trout seasonSeason
1
2
2
2
2
2
1
Grayling seasonSeason
1
2
2
2
2
2
1
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2
Alpine RhithrogenaHatch
1
2
2
1
Large Dark OliveHatch
1
2
2
1

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

Ranked for today
Brown Trout fly box
SW
Streamer / Woolly BuggerTop
6-10 · Pattern
High-confidence seasonal pick
Permits & access
Permit required — see local rules.
  • Fishing licence + permit from ribiške družine
  • No live bait.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Kanomljica
6.0 km
Marble trout · Marble brown hybrid trout · Brown trout
Cerknica (Idrijca tributary)
8.0 km
Marble trout · Marble brown hybrid trout · Brown trout
Hubelj
13 km
Marble trout · Marble brown hybrid trout · Brown trout
Kneža
16 km
Marble trout · Brown trout · Grayling
Vipava
17 km
87
Marble trout · Marble brown hybrid trout · Brown trout
Gallery · 6
  1. The Idrijca river near Most na Soči, Slovenia, with clear green water.
    Idrijca near Most na Soči
  2. The Idrijca flowing through the rocky Strug gorge between Podroteja and Idrijska Bela.
    Idrijca in the Strug gorge
  3. Wide landscape view of the Idrijca upstream from Idrijska Bela, Slovenia.
    Idrijca upstream from Idrijska Bela
  4. The Idrijca running through the Strug gorge with steep rocky banks.
    Idrijca in the Strug gorge
  5. The Idrijca at Spodnja Idrija, Slovenia, the river channel through the valley.
    Idrijca at Spodnja Idrija
  6. Terrain map of the venue
    Terrain map
Water quality (WFD)
  • Ecology: Good
  • Chemical: Unknown

WFD classification · SI62VT13

The full read · show the working · for Brown Trout · confidence 90%
How the 83 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow80 × 22%17.6
Clarity95 × 18%17.1
Feeding Time60 × 13%7.8
Pressure80 × 7%5.6
Insect activity59 × 12%7.1
Conditions total= 83
Can you trust it?
Water temperaturelive gauge readinggauge
Level / flowon-river gaugeobserved
Prey activitymodelled from regional profilemodelled
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 March → 30 September
  • Grayling 16 May → 30 November

    Slovenian common default: grayling 16 May – 30 November (lipan). Slovenia is permit and fishing district controlled — dates may vary by specific water. Always check the Ribiška Družina (fishing district) permit for the specific beat. The Soča, Idrijca, and Sava system hold world-class grayling alongside marble trout.

    Prime sport 1 September → 30 November

  • Marble trout 1 April → 31 October
Related guides
Grayling Playbookgrayling tacticsAlpine Streamsmountain entomologyMarble TroutSoča system
Booking & contacts