Yellowstone River Fishing Report: Cutthroat, Rainbows, and Browns Feeding on Tricos and BWOs

Artificial Lure here, bringing you the Yellowstone River fishing report for September 17, 2025—straight from the gravel bars, side channels, and cottonwood bends that make the Yellowstone one of Montana’s crown jewels for anglers.

It’s a crisp one this morning with overnight lows in the low 40s, but we’re looking at a bluebird, classic fall day. Expect highs to flirt with the low 70s by afternoon, under clear Montana skies and light northwest breezes. Sunrise hit at 6:58 a.m. and we’re looking at sunset at 7:34 p.m. No tides to track on this river—the Yellowstone runs wild and free, undammed for 692 miles.

Flows are holding steady and clear, just a little lower than average for mid-September thanks to a long, dry summer, but that means more gravel and better walk-wade access. Water temps overnight dropped into the upper 50s, and with these clear nights and warm afternoons, expect the fishing to really pick up late morning through midafternoon as things warm on the surface.

Trout are definitely shifting into their fall pattern. Recent catches, reported by Montana Outdoor, include solid numbers of Yellowstone cutthroat, rainbows, and browns—especially in the Paradise Valley stretch from Emigrant down to Big Timber. the trout are moving up into the riffles and tailouts, taking advantage of September’s juicy hatches. Don’t be surprised to find pods of rising fish sipping in the slicks, especially with the tricos still lingering on sunny mornings, and blue-wing olives popping off in the afternoons.

Best bets today: Start the morning with a size 20 trico spinner or spent-wing pattern if you see noses poking up, but don’t be afraid to switch to a parachute Adams or BWO emerger around lunchtime. If the surface bite fades, nymphing is money right now—try a beadhead pheasant tail or smaller Frenchie dropped below a chubby Chernobyl. Late summer grasshoppers are still hanging tough along the banks, so a tan or olive hopper with a smaller dropper (think lightning bug or Prince) has been pulling up chunky browns from undercut banks.

Streamer junkies should take note: as water temps gradually cool, some of the biggest browns get aggressive—swinging an olive or black sculpin pattern early or late in the day has produced some true slabs in the Livingston stretch and below. Just give the runs a rest between casts; those fish are getting wary, but they will move for a well-placed bugger.

From the latest Montana reports, the main action is in classic haunts:
- The “Grey Bear Reach” just east of Livingston is turning out plenty of 14–18” cutthroat and bows holding below riffle corners.
- Downriver, the Yankee Jim Canyon stretch has been hotter for browns, especially in the boulder runs and deeper tailouts.

Word to the wise: If you’re targeting whitefish, small nymphs like zebra midges or red copper johns fished deep will put you into the numbers game, especially as colder water pushes the whites into bigger schools.

Given recent news, remember to be mindful: There was a bear encounter on the Turbid Lake Trail on September 16, so keep your bear spray at the ready if you plan to hike into less-accessible stretches near Yellowstone Park. Stick to pairs or groups and stay loud when bushwhacking banks.

With fall setting in, don’t forget antelope and deer hunters may also be out, but be advised Montana Fish, Wildlife & Parks reports a possible uptick in deer diseases along the river corridor. It’s not a worry for fish, but stay alert and keep your eyes peeled for wildlife acting odd—report anything strange to FWP.

That’s the wrap for today—tight lines out there, and be sure to pack an extra layer for those chilly September mornings. This is Artificial Lure, thanking you for tuning in to the Yellowstone River report. Don’t forget to subscribe so you never miss what’s biting on the Big Y. This has been a quiet please production, for more check out quiet please dot ai.

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This content was created in partnership and with the help of Artificial Intelligence AI