When is rainbow trout season in Idaho?

Idaho 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 Idaho bag limit for rainbow trout?

The Idaho daily bag limit for rainbow trout is 6 / day combined trout (rainbow + brown + brook + cutthroat) statewide; 2 / day + catch-and-release on listed quality-management waters. The possession limit is 12 in possession combined trout. Some named waters set a different limit — check the water-body overrides above.

What size rainbow trout can you keep in Idaho?

The Idaho size rule for rainbow trout is No statewide minimum on most waters; 16-20 in min on listed quality-management reaches (Henry's Fork Box Canyon + Last Chance + Harriman + South Fork Snake + Silver Creek). Trophy rule: Lake Pend Oreille Kamloops + Gerrard rainbow trout strain produces 20+ lb fish consistently; ID state-record rainbow trout 37 lb 0 oz Pend Oreille 1947 (historically world-record-class inland rainbow trout); Henry's Fork Box Canyon + Harriman State Park 'Railroad Ranch' fly-fishing-only catch-and-release reach; South Fork Snake River trophy tailwater; IDFG stocks ~3 million rainbow annually via Hagerman National Fish Hatchery (USFWS — country's largest trout hatchery complex).

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

Yes. Idaho 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 Idaho license — compare resident and non-resident Idaho fees on the state regulations page below.

Are there gear restrictions for rainbow trout in Idaho?

Yes. In Idaho, rainbow trout fishing carries these gear rules: Hook-and-line; trolling permitted; fly-fishing-only on Harriman State Park 'Railroad Ranch' + listed quality-management reaches; Live bait permitted on most waters; artificial-lures-only + barbless single hook on listed catch-and-release reaches; Ice-fishing tip-ups + jiggers permitted during winter season; IDFG Fishing Licence required ages 14+ ($30.50 res / $108.25 NR annual); Confirm current-year IDFG Fish + Game Rules for quality-management reach + season list.

Do specific Idaho waters have different rainbow trout rules?

Yes. 4 named Idaho waters carry rules that override the statewide rainbow trout regulation, including Lake Pend Oreille, Henrys Fork, South Fork Snake River, and 1 more. See the named water-body overrides above for the exact rule on each.

2026 regulation year

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

Oncorhynchus mykiss

Last updated May 27, 2026

Idaho rainbow trout fishery is anchored by Lake Pend Oreille (148 sq mi, 1,158 ft maximum depth — Idaho's largest lake by surface area + 5th-deepest natural lake in the country) — the historical world-record-class inland rainbow trout water, where the ID state-record rainbow trout (37 lb 0 oz, 1947) remains one of the largest inland rainbow trout ever caught. Pend Oreille's Kamloops rainbow trout + Gerrard rainbow trout strain support naturally-reproducing populations that grow to 20+ lb routinely — one of the only inland US lakes producing trophy rainbow trout consistently outside the Great Lakes steelhead program. The Henry's Fork of the Snake River (130-mile southeastern Idaho river — Island Park Reservoir + Big Springs headwaters through Box Canyon + Last Chance + Harriman State Park 'Railroad Ranch' + Pinehaven + Mesa Falls + Ashton + St. Anthony + Rexburg) is the most famous wild rainbow trout river in the West — Harriman State Park 'Railroad Ranch' is the legendary fly-fishing-only catch-and-release reach that defined modern dry-fly + technical-nymphing technique. The South Fork Snake River (65-mile tailwater from the WY/ID line east of Jackson WY downstream to the Henry's Fork confluence) carries trophy rainbow + brown trout + native Yellowstone cutthroat tailwater fishery. The Big Wood River, Silver Creek (Sun Valley spring creek — one of the most-named-but-difficult dry-fly waters in the West), Salmon Falls Creek + St. Joe River (panhandle wild westslope cutthroat + rainbow river) round out the wild rainbow + spring-creek tier. IDFG-managed Quality Management reaches carry 16-20 in min slot + catch-and-release-only protection on Henry's Fork Box Canyon + Last Chance + Harriman + South Fork Snake + Silver Creek + Henrys Lake + Bear Lake trophy reaches. The reservoir tier (Dworshak + Brownlee + Magic Reservoir + American Falls + Lake Cascade + Anderson Ranch + Mountain Home Reservoir) carries stocked rainbow trout fisheries alongside the kokanee + smallmouth + walleye + perch fishery. IDFG stocks ~3 million rainbow trout annually statewide via the Hagerman National Fish Hatchery (USFWS — country's largest trout hatchery facility complex, ~10 million trout annually across all species) + IDFG Niagara Springs + Crystal Springs + Sawtooth + American Falls + Mackay + Henrys Lake State Fish Hatcheries. 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; Henry's Fork Box Canyon + Harriman State Park 'Railroad Ranch' catch-and-release reach managed under IDFG special-regulation.

Bag & possession

Daily bag: 6 / day combined trout (rainbow + brown + brook + cutthroat) statewide; 2 / day + catch-and-release on listed quality-management waters
Possession: 12 in possession combined trout

Size, slot, trophy rules

Size: No statewide minimum on most waters; 16-20 in min on listed quality-management reaches (Henry's Fork Box Canyon + Last Chance + Harriman + South Fork Snake + Silver Creek)
Trophy rule: Lake Pend Oreille Kamloops + Gerrard rainbow trout strain produces 20+ lb fish consistently; ID state-record rainbow trout 37 lb 0 oz Pend Oreille 1947 (historically world-record-class inland rainbow trout); Henry's Fork Box Canyon + Harriman State Park 'Railroad Ranch' fly-fishing-only catch-and-release reach; South Fork Snake River trophy tailwater; IDFG stocks ~3 million rainbow annually via Hagerman National Fish Hatchery (USFWS — country's largest trout hatchery complex)

Gear restrictions

Hook-and-line; trolling permitted; fly-fishing-only on Harriman State Park 'Railroad Ranch' + listed quality-management reaches
Live bait permitted on most waters; artificial-lures-only + barbless single hook on listed catch-and-release reaches
Ice-fishing tip-ups + jiggers permitted during winter season
IDFG Fishing Licence required ages 14+ ($30.50 res / $108.25 NR annual)
Confirm current-year IDFG Fish + Game Rules for quality-management reach + season list

Named water-body overrides

Where statewide rules differ on specific Idaho waters:

Lake Pend Oreille
6 / day combined; ID state-record rainbow trout 37 lb 0 oz Pend Oreille 1947; Kamloops + Gerrard rainbow trout strain produces 20+ lb fish consistently
Henry's Fork of the Snake River
6 / day combined elsewhere with 16-20 in min on Box Canyon + Last Chance quality-management; CATCH-AND-RELEASE-ONLY on Harriman State Park 'Railroad Ranch' fly-fishing-only reach
South Fork Snake River
Trout 6 / day combined; 18 in min cutthroat TROPHY MANAGEMENT; brown trout 18 in min + 1 / day; rainbow trout 6 / day
Dworshak Reservoir
6 / day combined trout; Dworshak National Fish Hatchery (USFWS — country's largest steelhead hatchery facility by output)

Official source

Idaho Department of Fish and Game (IDFG) publishes the authoritative 2026 Idahofishing regulations. Always verify the current rule before fishing — emergency closures and in-season changes can override what's published here.

Visit official Idaho fishing regulations →

Emergency-order channel

Rainbow trout closures, slot-limit changes, and harvest pauses are posted to Idaho Department of Fish and Game's emergency-order feed — check it before any Idaho trip during the active season.

Frequently asked questions

When is rainbow trout season in Idaho?: Idaho 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 Idaho bag limit for rainbow trout?: The Idaho daily bag limit for rainbow trout is 6 / day combined trout (rainbow + brown + brook + cutthroat) statewide; 2 / day + catch-and-release on listed quality-management waters. The possession limit is 12 in possession combined trout. Some named waters set a different limit — check the water-body overrides above.
What size rainbow trout can you keep in Idaho?: The Idaho size rule for rainbow trout is No statewide minimum on most waters; 16-20 in min on listed quality-management reaches (Henry's Fork Box Canyon + Last Chance + Harriman + South Fork Snake + Silver Creek). Trophy rule: Lake Pend Oreille Kamloops + Gerrard rainbow trout strain produces 20+ lb fish consistently; ID state-record rainbow trout 37 lb 0 oz Pend Oreille 1947 (historically world-record-class inland rainbow trout); Henry's Fork Box Canyon + Harriman State Park 'Railroad Ranch' fly-fishing-only catch-and-release reach; South Fork Snake River trophy tailwater; IDFG stocks ~3 million rainbow annually via Hagerman National Fish Hatchery (USFWS — country's largest trout hatchery complex).
Do you need a license to fish for rainbow trout in Idaho?: Yes. Idaho 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 Idaho license — compare resident and non-resident Idaho fees on the state regulations page below.
Are there gear restrictions for rainbow trout in Idaho?: Yes. In Idaho, rainbow trout fishing carries these gear rules: Hook-and-line; trolling permitted; fly-fishing-only on Harriman State Park 'Railroad Ranch' + listed quality-management reaches; Live bait permitted on most waters; artificial-lures-only + barbless single hook on listed catch-and-release reaches; Ice-fishing tip-ups + jiggers permitted during winter season; IDFG Fishing Licence required ages 14+ ($30.50 res / $108.25 NR annual); Confirm current-year IDFG Fish + Game Rules for quality-management reach + season list.
Do specific Idaho waters have different rainbow trout rules?: Yes. 4 named Idaho waters carry rules that override the statewide rainbow trout regulation, including Lake Pend Oreille, Henrys Fork, South Fork Snake River, and 1 more. See the named water-body overrides above for the exact rule on each.

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