Gallatin River Fishing in May

May Fly Fishing on the Gallatin River

In May, the Gallatin River gradually goes from spring thaw to peak runoff. Snowmelt swells the river and degrades clarity. Fishing can be good during the earlier weeks of the month, but there's a countdown to June when the river becomes inhospitable for a few weeks.

Trout feed aggressively near banks and mid-river structures, but wading gets harder due to rising flows.

Gallatin River May Hatches

Blue-winged olives, March Browns, and Midges hatch with frequency in early May. Caddis become increasingly active in the Gallatin Valley sections and can provide some terrific dry fly fishing in the evenings when water levels are stable.


Bozeman Fly Fishing Guide Pro-Tip:

The river can be dirty this time of year but there are still good angling opportunities if you go North above the Taylor's Fork Creek near Big Sky, MT. The Gallatin River is normally clearer above this creek as it is the main source of sedimentary runoff. We like to nymph a Brown Pat's Rubberlegs #10 and a Red Sparkle Worm #10 along the banks.


Gallatin River Fly Fishing Techniques for May

Anglers wade carefully amid rising Gallatin River currents, intercepting trout targeting protein-rich foods. Short casts, tight to structure with weighted nymph rigs find some large Brown Trout as water levels rise and clarity starts to diminish.

Switch to heavy sink tips and dredge streamers through holding lies as the river rises.

Dry fly-fishing opportunities abound in the early part of May, so long as water levels and clarity remain stable.

Our Gallatin River Fly Box for May

Guided Fly Fishing Options in May

As the Gallatin’s flows swell and its color degrades later in May, we leverage our 23+ years of guiding to put our guests on the best waters available. The fishing around Bozeman is generally very good through late May on the Madison, but the Yellowstone and Gallatin become "unfishable" within the first week of May.

Our Bozeman guided fly fishing trips focus on the Madison River for both novice and experienced anglers throughout May.

The Missouri River fishing is fantastic from late April through mid-June, near Craig Montana. Many of our longtime customers have made a tradition of fishing with us for 2-3 days on the Missouri in May. Missouri River fishing guides are available during this time of the year and welcome anglers of all skill levels for day and multi-day trips.

Learn more about our Gallatin River fishing day trips in May – when conditions permit – by reaching out through our Contact Form. Guided trips can be booked online, via e-mail, or by calling us at 406-468-5019.