Freestone · Mixed · Navarra, ES

Río Arga

Río Arga — Puente la Reina

Navarra's principal river, an Ebro tributary flowing south through Pamplona.

Today · Closed season
Czech Nymph
Forecast · Today
Closed season
Out of season. Try elsewhere.
45% projected
Today's fly
Czech Nymph
Czech Nymph
Conditions on the water · Today
Live gauge
Level
Rising
1.21 m
Lifting fast
Water temp11.8°C
ClarityUnfishable
Weather12°C
WindN 15 km/h
Pressure1012 hPa
Rain · recent5.7 mm
Rain · ahead5.7 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
12°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
Hatch timeline · todayPeak at 12pm

12pm(now) — Autumn Olive

Stage: On emergersApproach: Emerger or dryActivity: 20%

Peak activity at 12pm — Autumn Olive

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
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
  • Use the exact tramo and daily-permit structure for the section you plan to fish rather than assuming one simple Arga rule.
What's coming
Plan ahead
5-day outlook
Other water nearby · 5
Río Ulzama
15 km
0
Brown trout
Río Erro
25 km
0
Brown trout
Bidasoa tributaries (Navarra side)
32 km
0
Brown trout · Sea trout
Río Urrobi
28 km
Brown trout
Río Irati
35 km
Brown trout
Gallery · 2
  1. Río Arga — Puente la Reina
    Puente la Reina
  2. Terrain map of the venue
    Terrain map
About this water

The Arga rises in the western Pyrenees and joins the Aragón before reaching the Ebro (Mediterranean drainage — no Atlantic salmon access). Limestone and granite headwaters transition to sandstone near the city. Productive brown trout water with pool-and-run structure. Dry fly and nymphing for summer trout in clear upper reaches; water turns brownish during spates.

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

WFD classification · ES091MSPF546

The full read · show the working · for Brown Trout · confidence 75%
How the 0 is built — score × weight = contribution
Temperature100 × 28%28.0
Flow60 × 22%13.2
Clarity95 × 18%17.1
Feeding Time45 × 13%5.9
Pressure80 × 7%5.6
Insect activity42 × 12%5.0
Conditions total= 75
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
Prey activitysurvey-backed invertebrate datasurvey
What would change the calculation
The dawn and dusk windows score higher than the midday lull.
Directions
Apple MapsGoogle Maps
Seasons & zones
  • Trout 1 May → 30 June

    RSS Arga–Ultzama basin (922 permits in 2026). All catch-and-release. Extendable to 15 Jul by resolution. Daily basin permit required. Tramo-specific rules apply — check the official web app for stretch-level status.

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

Río Arga is a freestone river in Navarra, Spain. It sits at about 413 m above sea level. The river is described as roughly 145 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; nymph; wet fly. Level and flow data for this water is linked from 3 gauges. Its Water Framework Directive ecological status is recorded as moderate. Nearby waters in our listings include Río Ulzama at 15 km, Río Erro at 25 km and Río Urrobi at 28 km.