Freestone · Sedimentary · Honshū

Tama River (upper / Okutama)

Tama River, Mitake Valley

The upper Tama at Okutama is Tokyo's mountain river — cold, managed keiryu within reach of the city, stocked and looked after by the local co-operative, where yamame, iwana and rainbows hold in clear pools beneath wooded ridges.

Poor · Rainbow Trout
Cicada (foam semi pattern) · 6-10
Poorlive now
Not the day for it
Low and clear — careful approach country. A morning for the obvious fish only.
90% confidence
What moved it
  • LevelLight rain recentlyNo gauge reading
  • Water temp22.5°C
  • ClarityClear
Today's fly
CI
Cicada (foam semi pattern)6-10
High-confidence seasonal pick
Conditions on the water
Estimate
Level
Light rain recently
No gauge reading
Water temp22.5°C
ClarityClear
Weather26°C
WindNW 5 km/h
Pressure1006 hPa
Rain · recent6.2 mm
Rain · ahead15.2 mm

No gauge on this water — readings are regional estimates from weather, not a live gauge.

Water temperature for Rainbow Trout
Warm — slow
23°C est.ideal 10–18°C
0°14°28°
How to fish it · for Rainbow 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 22.5°C. This is the line where catch-and-release kills brown trout. Do not fish for them today.
Likely species
Mayflies
  • Iron blue mayflyMost likely
    #16–18 · Dun
    Cold, grey day — the dun sits long. Good dry-fly water.
  • Blue-winged oliveAlso possible
    #16–18 · Dun
    Duns are up; a sherry spinner fall may follow.
  • Green drakeAlso possible
    #8–10 · Spinner
    Spinners on the water now — the big fish move for these.
  • Large dark oliveAlso possible
    #14–16 · Emerger
    Dead-drift the emerger — it's sitting in the film.
Caddisflies
  • GrannomMost likely
    #14–16 · Pupa
    Pupa first, then dries as the adults come off.
  • Satin sedgeAlso possible
    #12–14 · Egg-laying
    Skitter it at dusk — this one's fished, not dead-drifted.
Hatch timeline · todayPeak at 6am

Hatch predictions

Today's headline hatch shown — see all 4 active hatches hour by hour with Pro.

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Beyond the hatch · worth watchingambient prey

Hatch predictions

Top prey shown — see all 3 with Pro.

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Through the year
0–3 scale · August highlighted
J
F
M
A
M
J
J
A
S
O
N
D
Stenopsyche CaddisHatch
2
3
3
2
Cicada (Semi)Hatch
2
2
GrannomHatch
2
2
Evening SedgeHatch
2
3
3
3
2

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

Ranked for today
Rainbow Trout fly box
Permits & access
Permit required — see local rules.
  • Local co-operative yugyoken required (day/annual ticket); managed stocked reaches with method rules
  • Confirm before fishing.
What's coming
Plan ahead
5-day outlook
Water here around 23°C. Nothing cooler within range — carry a thermometer.
Gallery · 2
  1. Tama River, Mitake Valley
    Upper Tama at Mitake Valley
  2. Terrain map of the venue
    Terrain map
About this water

The upper Tama at Okutama is Tokyo's mountain river — cold, managed keiryu within reach of the city, stocked and looked after by the local co-operative, where yamame, iwana and rainbows hold in clear pools beneath wooded ridges. The accessible face of Japanese stream fishing, busy but genuine.

Under the surface

Tokyo's home mountain river, running cold and clear through the wooded Okutama hills within reach of the city. A managed, stocked co-operative water — yamame, iwana and rainbow in pools and pocket runs — busy at weekends but a true keiryu all the same.

Wading: Accessible but slick rock, weekend crowds

  • River
  • Sedimentary
  • Partly confined
  • Pool riffle
  • Pocket water
Conservation note

Stocked rainbow with wild white-spotted char (iwana) and yamame.

The full read · show the working · for Rainbow Trout · confidence 90%
How the 12 is built — score × weight = contribution
Temperature6 × 28%1.7
Flow80 × 22%17.6
Clarity85 × 18%15.3
Feeding Time60 × 13%7.8
Pressure75 × 7%5.3
Insect activity69 × 12%8.3
Limiting factor: Water temperature (22.5°C) is outside Rainbow Trout's preferred range (10–18°C)= 56
Can you trust it?
Water temperatureair-to-water estimateestimated
Level / flowon-river gaugeobserved
What would change the calculation
Cooler water — back toward the 10–18 °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
  • Char late February to April → late September to mid-October

    Honshu/Shikoku/Kyushu keiryu are managed by local fishery co-operatives — a yugyoken (day/annual ticket) is required, and most streams close around 30 September / mid-October for spawning. Species are surfaced in prose only (no engine slugs for yamame, amago or iwana). Legal status: guidance_not_permission.

Related guides
Euro Nymphingsubsurface methods
Booking & contacts