San Juan River Fishing Report — September 17, 2026

It finally happened.

As of September 17, the San Juan River has dropped to 350 CFS.

The San Juan is a tailwater, so even with the lower flows, we still have cold water coming out of Navajo Dam and happy trout. What 350 CFS does change is accessibility. This is an excellent wade flow, and with less water in the river, fish begin concentrating into more predictable lanes, buckets, and feeding areas.

If you’ve wanted to learn the San Juan on foot, this is a great time to do it.

We’ve also been getting some much-needed rain throughout September. Hopefully that trend continues and starts putting some water back into Navajo Reservoir.

September Fishing

September is one of our favorite months because almost everything is on the table.

Nymphing, dry flies, streamers, and Trout Spey are all producing.

The river is extremely buggy right now. Just before the flow reduction, I saw one of the largest Blue-Winged Olive hatches I’ve seen all season. As we move deeper into September, we really start keying in on Baetis and other small mayflies, while midges continue to make up a huge portion of what these fish are eating.

There are still some PMDs around as well.

Pay attention to where the fish are feeding. A lot of trout will suspend in the middle and upper portions of the water column, especially once the bugs get moving. You don’t always need to be dragging a heavy rig along the bottom.

Start deeper in the morning if necessary, then shorten and lighten those rigs as activity increases.

Nymphs

With rain and changing conditions, we’re still fishing plenty of classic San Juan junk:

• Leeches
• Worms
• Egg patterns
• Red larva

Once the water warms and the bugs become more active, we start transitioning into lighter, shallower presentations.

Some of our current favorites:

• Flashback Pheasant Tails
• Root Beer Baetis
• FSC Baetis
• Chocolate Foam Wings
• Scintillas
• KF Emergers
• RS2s — gray and chocolate

The FSC Baetis has been especially good this time of year. I’ll attach a video showing that pattern.

One thing I notice every September is that even when trout are feeding in a pile of midges, they’ll often pick out a Baetis pattern. For whatever reason, they seem to really key in on them this time of year.

Dry Flies

The dry fly fishing has been good, but when the fish get picky, think low-profile patterns that sit down in the film.

We’ve been fishing:

• Hare’s Ear Last Chance Cripples
• Charlie Craven’s Mole Fly
• IOBOs
• Sprout Midges
• Small Baetis patterns

You can even grease up an RS2 and fish it as a dry. It sounds simple, but it can be an excellent September pattern when fish are eating emergers just underneath the surface.

Streamers

Streamer fishing continues to be good.

We’re fishing plenty of tandem rigs with:

• Sculpzillas
• Sparkle Minnows
• String Leeches

And you can absolutely still throw some bigger flies.

We’re already seeing brown trout coloring up and moving around, and I’ve seen fish beginning to cut redds. The browns are active and still eating streamers, but as spawning activity increases, keep an eye out for active redds and give those spawning fish some room.

Trout Spey

At 350 CFS, this is also a really fun time to cover the river with a Trout Spey rod.

We’re swinging:

• Trombones
• Sculpzillas
• String Leeches
• Other small baitfish patterns

If you have a switch rod or something with a little more horsepower, you can start turning over some bigger offerings too.

I actually went out just before the state park closed the other day and fed one a mouse doing exactly that.

Bottom Line

350 CFS. Cold water. Great wade flows. Lots of bugs.

September gives you a little bit of everything on the San Juan. You can nymph in the morning, hunt heads with dry flies once the bugs get moving, swing a Trout Spey rod through likely water, or spend the day throwing streamers.

If you’ve wanted to really learn the river and understand where these fish live at lower flows, this is one of the better times of the year to come do it.

Things are good on the San Juan.