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Insects

Brown troutRainbow troutMountain whitefishBrook troutCutthroat troutSteelheadEuropean graylingMarble troutSea-run brown troutResident brown trout

Techniques

Reading waterMatching a hatchNymphingDry-fly presentationStreamer fishingSwinging a flyCatch and release, done properlyTying flies you will actually fish

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Rivers
White River, ArkansasDavidson RiverPenns CreekLetort Spring RunFarmington RiverPere Marquette RiverNorth Umpqua RiverDeschutes RiverSan Juan RiverFryingpan RiverYellowstone RiverBighorn RiverTraun RiverBeaverkill RiverRío GrandeGreen River below Flaming GorgeRiver WharfeHenry's Fork of the SnakeSoča RiverAu Sable RiverTongariro RiverSouth Platte — Deckers and CheesmanRiver TestMadison River
Brown troutRainbow troutMountain whitefishBrook troutCutthroat troutSteelheadEuropean graylingMarble troutSea-run brown troutResident brown trout
Reading waterMatching a hatchNymphingDry-fly presentationStreamer fishingSwinging a flyCatch and release, done properlyTying flies you will actually fish

San Juan River

Sixteen kilometres of midge-and-mayfly water where a 50-fish day is unremarkable.

Region
Navajo Dam to Farmington, New Mexico, United States
Country
United States
Water type
Deep-release tailwater with a famously consistent midge population
Species
rainbow, brown
Length
16 km
Typical flow
250–1,000 cfs on the quality water; the river is wadeable across most of that range
Season
Fishable twelve months; spring and autumn are the busiest and the best
Best months
Mar · Apr · May · Sep · Oct · Nov
Published
2026-09-28

By The Fly Desk

Fly plate: Chimera, grey
Plate 1 · dressing
Aquatic insect plate: Midges (Chironomidae)
Plate 2 · insect

Hatch timeline

  • Jan · 10:00-15:00Midges (Chironomidae) Pupa and adult

    #20-26 · Jan · Hatch

  • Mar · 11:00-15:00Blue-Winged Olive (Baetis) Emerger

    #20-24 · Mar · Hatch

  • Apr · 10:00-16:00Midges (Chironomidae) Adult cluster

    #22-26 · Apr · Hatch

  • May · 18:00-21:00Caddis (Hydropsyche) Adult, evening

    #16-18 · May · Hatch

  • Jul · 09:00-12:00Pale Morning Dun (Ephemerella) Dun

    #18-20 · Jul · Hatch

  • Sep · 08:00-11:00Trico (Tricorythodes) Spinner fall

    #24-26 · Sep · Hatch

  • Nov · 12:00-15:30Blue-Winged Olive (Baetis) Dun

    #22-24 · Nov · Hatch

Matched fly box

PatternImitatesSizeTechnique
Chimera, greyChironomid cluster#22-24Fish it 40 cm under a foam indicator in the slow water at the head of Texas Hole.
San Juan Worm, tanAquatic worm#12-14Only when the release is murky; it is the first fly to stop working when water clears.
BWO Foam EmergerEmerging Baetis#22Dead drift on a 5-metre leader, 6X, in the film over the weed beds.
RS2, chocolateBaetis emerger#22-24Point fly in a two-fly rig; the take usually comes in the first two seconds.
Woolly Bugger, blackLeech#8Swing through the Braids at dusk when nothing is showing on the surface.

The river

The San Juan's quality water runs from Navajo Dam down to the confluence with the Animas near Farmington, and it is one of the most productive trout rivers in North America. Fish counts run into the thousands per kilometre, which changes the tactics: the fish are not selective about pattern as much as they are about depth and drag. The Texas Hole below the dam is the famous spot; the wade water at Simon Canyon and the Braids get a fraction of the pressure.

On this river

Depth before pattern

On the San Juan the difference between a 10-fish day and a 50-fish day is usually 30 cm of depth and a metre of drag. Start shallow with a small fly and add depth in 15 cm steps until you start hooking fish; then leave the rig alone. Changing patterns before you have found the fish's level is the most common way to waste a morning here.

Fishing the Texas Hole properly

The Hole is a slow, deep bowl, not a run. Fish it from the tail upstream, wading as far as is safe, and cover it in a fan rather than straight upstream — the fish hold in a ring around the deepest point rather than in the middle. The first two hours of daylight are worth more than the rest of the day combined.

Small flies, long leaders

The San Juan's midges are #22 to #26 and the water is clear, so a 5.5-metre leader tapering to 7X is normal equipment, not an affectation. Cast with an open loop to avoid tailing, and treat the leader as part of the presentation: if the tippet lands in a heap, the fly is dragging even when the indicator looks fine.

Licence and rules

New Mexico requires a fishing licence for anyone 12 and older, and a separate habitat stamp for most waters. The San Juan below Navajo Dam is catch-and-release, artificial-flies-only from the dam down to the US 64 bridge, with barbless hooks encouraged. The Navajo Nation boundary starts downstream of the quality water — a tribal permit is a separate purchase and the rules there are not the same.
When should I come?

The best months are Mar · Apr · May · Sep · Oct · Nov. Fishable twelve months; spring and autumn are the busiest and the best

What licence do I need?

New Mexico requires a fishing licence for anyone 12 and older, and a separate habitat stamp for most waters. The San Juan below Navajo Dam is catch-and-release, artificial-flies-only from the dam down to the US 64 bridge, with barbless hooks encouraged. The Navajo Nation boundary starts downstream of the quality water — a tribal permit is a separate purchase and the rules there are not the same.

How does the water behave?

Navajo Dam releases vary more than the fishing reports admit: the same stretch can be 300 cfs in the morning and 900 cfs after lunch. The quality water is wadeable up to about 1,000 cfs, and the crossing points at Texas Hole become waist-deep above 700 cfs. Water temperature holds near 8°C downstream of the dam, which is why midges hatch in January.

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