Sun River
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.
October Caddis
- 01October Caddis, BWOs, and Mahogany Duns are becoming active.
- 02Terrestrial fishing (hoppers, ants) remains strong along banks.
- 03River flows are unstable due to irrigation, requiring careful water selection.
- 04Air temperature is a comfortable 53°F and overcast.
- 05Nymphing with Flashback Hare's Ear and Zebra Midges is consistently effective.
Past reports week by week
5 weeksWhat to tie on
Picked from reports, hatches and the season. Tap a fly for the recipe and where else it works.
October Caddis (Dry)
Regional intelligence indicates larger October Caddis are becoming a significant factor in fall, making this a prime dry fly for the Sun River.
Buy at AmazonBlue-Winged Olive (BWO) Comparadun
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.
Buy at AmazonSchroeder’s Parachute Hopper
Terrestrial fishing remains strong in early fall, and hoppers are a substantial food source, as indicated by regional reports.
Chernobyl Ant
Terrestrial fishing, including ants, remains strong in early fall according to regional intelligence.
Buy at AmazonMahogany Dun
Regional reports indicate Mahogany Dun patterns are starting to appear in fall, offering dry fly opportunities for trout.
Buy at AmazonPurple Haze
Regional reports mention Purple Haze as an effective early fall attractor, particularly for cutthroat trout.
Buy at AmazonFlashback Hare's Ear Nymph
A versatile and reliable searching nymph, effective year-round, especially with the Sun River's characteristic unstable flows.
Zebra Midge (Black)
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.
Where to fish and who to ask
Gibson Dam Tailwater
Highly productive tailwater section below the dam.
Simms Fishing Access
Further downstream access to varied river conditions.
Get Sun River reports by email
Save this water and we'll email you a weekly summary of conditions, hatches and what's working.
Montana season by season
What changes on the water through the year, with the flies for each season.
Read before you go
Winter Fly Fishing: Essential Cold Weather Tips & Tactics
Master winter fly fishing with proven cold weather strategies, gear selection, and tactics for catching trout when temperatures drop.
Fly Line Types Guide: WF, DT, Running & Shooting Heads
Master fly line selection with our comprehensive guide to weight forward, double taper, running lines, and shooting heads for every fishing situation.
Best Fly Fishing Waders of 2025 – Breathable vs. Neoprene
Expert comparison of breathable and neoprene waders with top 2025 models for every budget and fishing condition.
Felt vs. Rubber Sole Wading Boots: What's Legal Where
Essential guide to felt vs. rubber sole wading boots, plus state-by-state regulations to keep you legal on the water.
Fly Fishing Pack vs Vest: Which Setup Is Right for You?
Compare fly fishing packs and vests to find the perfect gear setup for your angling style and fishing conditions.
Best Fly Fishing Sunglasses: Lens Color & Polarization Guide
Master lens color selection and polarization technology for superior vision and fish detection on the water.
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), Blue-Winged Olive (BWO) Comparadun (90% confidence), Schroeder’s Parachute Hopper (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.