The Boulder River crests in late June and then starts to drop, quickly coming into “prime’ fly fishing condition in early July. The window when floating the lower river is optimal lies between July 4th and mid-July when streamflow levels are between 900 and 1500 CFS. These levels enable safe passage while navigating the myriad “rock gardens” with productive wading opportunities throughout the day.
Anglers fishing the Boulder River in July can expect pleasant wet-wading conditions, beautiful scenery and an abundance of 10-14” wild trout.
The upper river begins to fish well and access is abundant along the forest service road leading to the headwaters. This becomes small stream fly fishing as the summer progresses and fine tippets with medium-sized dry/dropper rigs is the angling standard.
Wade fishing becomes the standard for Boulder River fly fishing by late July. Although wading is difficult as the rocks are rounded and slippery, lower river levels do make accessibility easier for mobile anglers willing to walk below the high water mark for long distances.
This Montana freestone river flows through vast tracts of agricultural farmland along the lower 35 miles. Terrestrial insects such as grasshoppers, ants, beetles, and Spruce Moths become key food sources for the Boulder River Trout by late July.
Nocturnal-hatching Golden Stones, Caddis, and PMDs are the most prevalent hatching insects on the river in July. The hatches and abundance of insects on the lower river are far superior to the upper river sections.
Slow-rising trout can be found along the riffle edges and bankside seams, next to rocks during PMD hatches and spinner falls. Look for larger fish to feed selectively on Rusty Spinners in the Boulder Forks area near sundown in mid-late July.
Dry and dry-dropper rigs are the summertime mainstays for anglers fishing in Montana on the Boulder River, near Big Timber. Attractor dry fly patterns like a Chubby Chernobyl, Royal Wulff, or Purple Haze in sizes 12-16 fished solo on 9’ leaders and 5X tippet consistently produce results. Hopper patterns with a small, weighted nymph dropper like a Purple Lite-Brite Perdigon or Spanish Bullet in sizes 16-18 are anglers' favorites.
Leave the nymph and streamer rigs in the truck when fly fishing the Boulder River in July – dries or dry-dropper rigs should suffice.
Floating the Boulder River - when the flows are just right - is an exceptional Montana fly fishing experience. The scenery, water, and the Montana trout all come together to create a day trip experience that can be second to none. If you are lucky enough to be fishing with our Bozeman fly fishing guides during this time, then consider asking to include a day trip on the Boulder River to your multi-day itinerary.
The window for prime fishing conditions on the Boulder River is typically during the first two weeks of July. This, however, is primetime everywhere in Montana so it is easy to overlook the Boulder River as it can be difficult to navigate and guests need to be physically fit to assist with boat launches and portaging around navigational hazards.
This is dry/dropper or dry fly only fishing suited best for intermediate to advanced fly anglers. Anglers can expect a flurry of activity as our guides navigate through myriad obstacles while offering quick instructions as they call out the next spot to place your flies.
Reservations with our Bozeman fly fishing guides can be secured online, via e-mail, or by calling us at 1-406-468-5019. Fins and Feathers Guide Service has been outfitting Montana fly fishing trips for over two decades and welcomes anglers of all skill levels on our Montana fly fishing trips near Bozeman.