Updated October 15, 2026

    Sun RiverFishing report · river in Montana

    The Sun River flows from the Bob Marshall Wilderness and provides a range of fly fishing environments. The tailwater section below Gibson Dam is particularly noted for its robust rainbow and brown trout, while the upper freestone sections offer a more secluded experience with native cutthroat.

    Bite report · week of Oct 4

    October Caddis

    1. 01October Caddis, BWOs, and Mahogany Duns are becoming active.
    2. 02Terrestrial fishing (hoppers, ants) remains strong along banks.
    3. 03River flows are unstable due to irrigation, requiring careful water selection.
    4. 04Air temperature is a comfortable 53°F and overcast.
    5. 05Nymphing with Flashback Hare's Ear and Zebra Midges is consistently effective.

    Past reports week by week

    5 weeks

    What to tie on

    Picked from reports, hatches and the season. Tap a fly for the recipe and where else it works.

    dry

    October Caddis (Dry)

    October Caddis (Dicosmoecus) adult
    #6#8#10

    Regional intelligence indicates larger October Caddis are becoming a significant factor in fall, making this a prime dry fly for the Sun River.

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    terrestrial

    Schroeder’s Parachute Hopper

    #6#8#10

    Terrestrial fishing remains strong in early fall, and hoppers are a substantial food source, as indicated by regional reports.

    dry

    Blue-Winged Olive Comparadun

    #18#20#22

    Regional intelligence suggests BWOs are beginning to appear, and this low-profile dry fly is excellent for selective trout feeding on emergers and adults during fall hatches.

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    dry

    Mahogany Dun

    Paraleptophlebia adult
    #14#16#18

    Regional reports indicate Mahogany Dun patterns are starting to appear in fall, offering dry fly opportunities for trout.

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    dry

    Chernobyl Ant

    Terrestrial (general)
    #8#10#12

    Terrestrial fishing, including ants, remains strong in early fall according to regional intelligence.

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    dry

    Purple Haze

    Attractor (no specific hatch)
    #14#16#18

    Regional reports mention Purple Haze as an effective early fall attractor, particularly for cutthroat trout.

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    nymph

    Flashback Hare's Ear Nymph

    #14#16#18

    A versatile and reliable searching nymph, effective year-round, especially with the Sun River's characteristic unstable flows.

    nymph

    Zebra Midge

    Midge pupa (Chironomidae)
    #18#20#22#24

    Midges are a primary and consistent food source year-round, and this pattern is highly effective for enticing finicky trout, especially with unstable river flows.

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    Where to fish and who to ask

    1Gibson Dam TailwaterGibson Dam Tailwater2Simms Fishing AccessSimms Fishing Access3Willow Creek AccessWillow Creek Access
    Access
    1

    Gibson Dam Tailwater

    Highly productive tailwater section below the dam.

    47.472°N 112.756°WUSGS 06096500Directions
    2

    Simms Fishing Access

    Further downstream access to varied river conditions.

    47.700°N 112.000°WDirections
    3

    Willow Creek Access

    Public access offering wade fishing below the dam.

    47.580°N 112.500°WDirections

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    Montana season by season

    What changes on the water through the year, with the flies for each season.

    Quick answers

    Common questions about Sun River.

    What flies work best on Sun River?

    Our top scored fly patterns for Sun River right now are October Caddis (Dry) (95% confidence), Schroeder’s Parachute Hopper (90% confidence), Blue-Winged Olive Comparadun (90% confidence). These picks are scored from recent fishing reports, hatch data, and seasonal patterns.

    What fish species are in Sun River?

    Sun River holds Rainbow Trout, Brown Trout, Westslope Cutthroat Trout. See the species links on this page for fly recommendations and seasonal behavior for each.

    What are current flow conditions on Sun River?

    Live USGS streamflow readings for Sun River are charted in the sidebar of this page and updated automatically from the nearest gauge.

    Is Sun River fishing well right now?

    We publish a fresh bite report for Sun River each week based on recent on-the-water intel. The current report — with conditions, hatches, and what's producing — is on this page.