When is rainbow trout season in Montana?

Montana keeps rainbow trout open to fishing year-round for the 2026 regulation year — there is no closed season, though the daily bag and size limits below still apply every day.

What is the Montana bag limit for rainbow trout?

The Montana daily bag limit for rainbow trout is Part of the district combined-trout limit (rainbow + brown + golden + grayling, plus cutthroat in Central/Eastern): Western lakes 5 / day (only 1 over 22 in) + rivers 3 / day (only 1 over 14 in); Central lakes 5 + rivers 5 / day (only 1 over 18 in); Eastern lakes + rivers 5 / day. Catch-and-release for rainbow on the entire Beaverhead and most of the Madison. The possession limit is 10 in possession combined trout (Western + Central lakes); 5 in possession Western/Central rivers. Some named waters set a different limit — check the water-body overrides above.

What size rainbow trout can you keep in Montana?

The Montana size rule for rainbow trout is No statewide minimum length; 'only 1 over' large-fish caps on listed river reaches (22 in Western, 18 in Central rivers); catch-and-release for rainbow on the Beaverhead + Madison. Trophy rule: MT state-record rainbow trout 30 lb 0 oz Beaverhead River 1996 (Twin Bridges, Beaverhead County — one of largest rainbow trout state records in lower 48 outside Pacific anadromous waters); Madison + Bighorn + Missouri + Beaverhead wild-trout tailwater fisheries among densest catchable trout populations in country (5,000-8,000 fish per mile); FWP does NOT stock rainbow on major blue-ribbon rivers (wild self-sustaining populations protected from hatchery genetic introgression).

Do you need a license to fish for rainbow trout in Montana?

Yes. Montana requires a valid fishing license to fish for rainbow trout, with the usual exemptions for young children, state free-fishing days, and some senior or disabled-veteran categories. A license is valid only in the state that issued it, so non-residents need a Montana license — compare resident and non-resident Montana fees on the state regulations page below.

Are there gear restrictions for rainbow trout in Montana?

Yes. In Montana, rainbow trout fishing carries these gear rules: Hook-and-line; trolling permitted; fly-fishing-only on listed quality-management reaches; Live bait prohibited on most blue-ribbon trout streams (Madison + Bighorn + Missouri tailwater + Beaverhead + Big Hole + Yellowstone + Smith); artificial-lures-only or fly-only on listed reaches; Barbless single hook required on listed catch-and-release reaches; Conservation License + Fishing License required (AIS Prevention Pass required for anglers 16+): $8 res Conservation + $21 res season fishing + $2 res AIS / $10 NR Conservation + $100 NR season fishing + $7.50 NR AIS; Confirm current-year FWP Fishing Regulations for District-by-District quality-management reach + season list.

Do specific Montana waters have different rainbow trout rules?

Yes. 5 named Montana waters carry rules that override the statewide rainbow trout regulation, including Madison River, Bighorn River, Missouri River below Holter Dam, and 2 more. See the named water-body overrides above for the exact rule on each.

2026 regulation year

Montana Rainbow trout 2026 — Season, Bag Limit, Size Rules

Oncorhynchus mykiss

Last updated June 8, 2026

Montana rainbow trout fishery is the country's premier wild + naturally-reproducing rainbow trout destination in the lower 48 — Montana is one of only Western states with self-sustaining wild rainbow trout populations on virtually every blue-ribbon trout river (no stocking required to maintain density). The headline waters: the Madison River (183-mile river from the Madison + Firehole River confluence in Yellowstone NP through Hebgen Lake + Quake Lake + the '50-mile riffle' wade-fishing reach + Ennis Lake + Beartrap Canyon to the Missouri Headwaters at Three Forks MT) — the '50-mile riffle' below Quake Lake is the legendary continuous-pocket-water reach that defined modern western dry-fly + nymph technique (5,000+ catchable rainbow + brown trout per mile, FWP-managed wild-trout fishery, no stocking); the Bighorn River (Yellowtail Dam tailwater 13-mile blue-ribbon reach from Fort Smith MT downstream to Bighorn Access — 8,000+ catchable trout per mile, one of country's densest wild rainbow + brown trout populations); the Missouri River below Holter Dam (40+ mile blue-ribbon tailwater from Holter Dam through Wolf Creek + Craig + Cascade — ~5,000 fish per mile, FWP-managed wild brown + rainbow trout tailwater); the Beaverhead River (80-mile tailwater from Clark Canyon Reservoir at Dillon MT through Barretts + Pipe Organ + Beaverhead Canyon + Twin Bridges — MT state-record rainbow trout 30 lb 0 oz Beaverhead River 1996, one of largest rainbow trout state records in the lower 48 outside Pacific anadromous waters); the Big Hole River (153-mile river — wild rainbow + brown + brook + native arctic grayling fishery); the Yellowstone River (Paradise Valley + the 60-mile reach from Gardiner downstream to Livingston — wild rainbow + native Yellowstone cutthroat + brown trout). Hebgen Lake + Wade Lake + Cliff Lake (Beaverhead / Gallatin County natural + reservoir lakes adjacent to the Madison River) carry the still-water trophy wild rainbow + brown trout fishery. FWP-managed wild-trout reaches carry catch-and-release-only protection on the Madison '50-mile riffle' + Bighorn Yellowtail tailwater + Missouri Holter tailwater + Beaverhead + Big Hole reaches — Montana protects big fish with 'only 1 over' caps, not minimum-length quality-management slots. FWP does NOT stock rainbow trout on the major blue-ribbon rivers — wild self-sustaining populations are deliberately protected from hatchery genetic introgression. Open year-round on most waters; quality-management waters carry seasonal closures + harvest restrictions.

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Season

Open year-round Open year-round on most waters; quality-management waters carry seasonal closures; Madison + Bighorn + Missouri + Beaverhead + Big Hole tailwater wild-trout reaches managed under FWP wild-trout regulation.

Bag & possession

Daily bag: Part of the district combined-trout limit (rainbow + brown + golden + grayling, plus cutthroat in Central/Eastern): Western lakes 5 / day (only 1 over 22 in) + rivers 3 / day (only 1 over 14 in); Central lakes 5 + rivers 5 / day (only 1 over 18 in); Eastern lakes + rivers 5 / day. Catch-and-release for rainbow on the entire Beaverhead and most of the Madison
Possession: 10 in possession combined trout (Western + Central lakes); 5 in possession Western/Central rivers

Size, slot, trophy rules

Size: No statewide minimum length; 'only 1 over' large-fish caps on listed river reaches (22 in Western, 18 in Central rivers); catch-and-release for rainbow on the Beaverhead + Madison
Trophy rule: MT state-record rainbow trout 30 lb 0 oz Beaverhead River 1996 (Twin Bridges, Beaverhead County — one of largest rainbow trout state records in lower 48 outside Pacific anadromous waters); Madison + Bighorn + Missouri + Beaverhead wild-trout tailwater fisheries among densest catchable trout populations in country (5,000-8,000 fish per mile); FWP does NOT stock rainbow on major blue-ribbon rivers (wild self-sustaining populations protected from hatchery genetic introgression)

Gear restrictions

Hook-and-line; trolling permitted; fly-fishing-only on listed quality-management reaches
Live bait prohibited on most blue-ribbon trout streams (Madison + Bighorn + Missouri tailwater + Beaverhead + Big Hole + Yellowstone + Smith); artificial-lures-only or fly-only on listed reaches
Barbless single hook required on listed catch-and-release reaches
Conservation License + Fishing License required (AIS Prevention Pass required for anglers 16+): $8 res Conservation + $21 res season fishing + $2 res AIS / $10 NR Conservation + $100 NR season fishing + $7.50 NR AIS
Confirm current-year FWP Fishing Regulations for District-by-District quality-management reach + season list

Named water-body overrides

Where statewide rules differ on specific Montana waters:

Madison River
Rainbow CATCH-AND-RELEASE from the YNP boundary down; Quake Lake outlet to Varney Bridge ALL trout catch-and-release, artificial lures only, wade-only
Bighorn River
Central District river standard; 8,000+ catchable trout per mile; FWP-managed wild-trout tailwater
Missouri River below Holter Dam
Holter Dam to Cascade Bridge 3 trout / day, only 1 over 18 in; ~5,000 fish per mile; FWP-managed wild brown + rainbow trout tailwater
Beaverhead River
Rainbow trout CATCH-AND-RELEASE only (entire river); MT state-record rainbow trout 30 lb 0 oz Beaverhead River 1996
Big Hole River
Headwaters to Dickie Bridge combined trout 5 / day; Dickie Bridge to mouth catch-and-release only; arctic grayling catch-and-release (entire river)

Official source

Montana Fish, Wildlife & Parks (FWP) publishes the authoritative 2026 Montanafishing regulations. Always verify the current rule before fishing — emergency closures and in-season changes can override what's published here.

Visit official Montana fishing regulations →

Emergency-order channel

Rainbow trout closures, slot-limit changes, and harvest pauses are posted to Montana Fish, Wildlife & Parks's emergency-order feed — check it before any Montana trip during the active season.

Frequently asked questions

When is rainbow trout season in Montana?: Montana keeps rainbow trout open to fishing year-round for the 2026 regulation year — there is no closed season, though the daily bag and size limits below still apply every day.
What is the Montana bag limit for rainbow trout?: The Montana daily bag limit for rainbow trout is Part of the district combined-trout limit (rainbow + brown + golden + grayling, plus cutthroat in Central/Eastern): Western lakes 5 / day (only 1 over 22 in) + rivers 3 / day (only 1 over 14 in); Central lakes 5 + rivers 5 / day (only 1 over 18 in); Eastern lakes + rivers 5 / day. Catch-and-release for rainbow on the entire Beaverhead and most of the Madison. The possession limit is 10 in possession combined trout (Western + Central lakes); 5 in possession Western/Central rivers. Some named waters set a different limit — check the water-body overrides above.
What size rainbow trout can you keep in Montana?: The Montana size rule for rainbow trout is No statewide minimum length; 'only 1 over' large-fish caps on listed river reaches (22 in Western, 18 in Central rivers); catch-and-release for rainbow on the Beaverhead + Madison. Trophy rule: MT state-record rainbow trout 30 lb 0 oz Beaverhead River 1996 (Twin Bridges, Beaverhead County — one of largest rainbow trout state records in lower 48 outside Pacific anadromous waters); Madison + Bighorn + Missouri + Beaverhead wild-trout tailwater fisheries among densest catchable trout populations in country (5,000-8,000 fish per mile); FWP does NOT stock rainbow on major blue-ribbon rivers (wild self-sustaining populations protected from hatchery genetic introgression).
Do you need a license to fish for rainbow trout in Montana?: Yes. Montana requires a valid fishing license to fish for rainbow trout, with the usual exemptions for young children, state free-fishing days, and some senior or disabled-veteran categories. A license is valid only in the state that issued it, so non-residents need a Montana license — compare resident and non-resident Montana fees on the state regulations page below.
Are there gear restrictions for rainbow trout in Montana?: Yes. In Montana, rainbow trout fishing carries these gear rules: Hook-and-line; trolling permitted; fly-fishing-only on listed quality-management reaches; Live bait prohibited on most blue-ribbon trout streams (Madison + Bighorn + Missouri tailwater + Beaverhead + Big Hole + Yellowstone + Smith); artificial-lures-only or fly-only on listed reaches; Barbless single hook required on listed catch-and-release reaches; Conservation License + Fishing License required (AIS Prevention Pass required for anglers 16+): $8 res Conservation + $21 res season fishing + $2 res AIS / $10 NR Conservation + $100 NR season fishing + $7.50 NR AIS; Confirm current-year FWP Fishing Regulations for District-by-District quality-management reach + season list.
Do specific Montana waters have different rainbow trout rules?: Yes. 5 named Montana waters carry rules that override the statewide rainbow trout regulation, including Madison River, Bighorn River, Missouri River below Holter Dam, and 2 more. See the named water-body overrides above for the exact rule on each.

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