What Size Woolly Bugger For Trout? Fish Catching Machine

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Fly in a fly box, wooly bugger

The ideal-sized Woolly Bugger depends on where you’re fishing and the size of the fish you’re targeting. Generally, anglers successfully fish with Woolly Buggers between sizes 6-10. These medium-sized flies work well in various current speeds and depths. Always have numerous sizes on hand when fly fishing for trout. 

Every trout angler has their one fly they consider a cheat code. If they can’t find anything that’s working, they tie it on and hope for the best. The Woolly Bugger is always my go-to when I visit new water or can’t entice the fish. It represents various food sources and excites even the most stagnant fish. 

Woolly Bugger & Fish Size 

Woolly Buggers are the perfect fly to use if you have the potential to land a trophy fish. Since they represent everything from minnows to crayfish, trout of all sizes bite them. The larger the fish you can catch, the larger the Woolly Bugger you should have on hand. 

If I can catch fish between 15-25 inches, I’ll carry buggers ranging from size 2 to 10. Big fish don’t always want bigger flies, but if they act aggressively, I always throw on some of my largest flies if a true giant is willing to eat. When pursuing those giants, I start with a size 4 or 6 and work to smaller flies if those larger patterns aren’t working. 

When fishing water I don’t know well, I usually throw a size 6 or 8 Woolly Bugger. While they’re not the largest flies, they work for fish of all sizes. An 8-inch stocked trout can eat them, as well as a 20-inch trophy. Starting on the smaller end when you don’t know the water or the size of fish you can catch is always a safe bet.

You can switch to a larger pattern anytime, but give yourself a chance with a smaller Woolly Bugger. Anywhere from a size 6-10 is ideal. 

Woolly Bugger Sizes Depend on the Type of Water 

When choosing flies, I start with the size of fish I can catch and then move to the type of water I’m fishing. I always want my flies to look natural and realistic in the water. I don’t want to throw a size 0 Woolly Bugger in a tiny stream. It would look out of place, and it may not be possible for fish to eat it. The size of the fly matters just as much as the type of fly you use. 

Danny standing in the water fly fishing a small stream in Arizona
Fly fishing a small stream in Arizona

Small Creeks

I fish Woolly Buggers ranging from size 6 to 12 in small creeks. I’ll start with a size 8 or 10 and make changes depending on what’s happening. If I see a large fish, I’ll throw on a size 6 and see if I get any follows or flashes. 

I know I have the proper pattern when seeing fish consistently flash or follow my fly. However, consistent follows with minimal strikes might mean I have the wrong size. When I see fish pursuing, I’ll always switch to a smaller fly, but I can’t get anything to take my fly. 

Small creeks are challenging to fish. Sticking with smaller flies is a good place to start to set yourself up for success. Again, you can always move to a bigger fly if the fish want it. It’s frustrating to ruin a hole with a massive fly, throw a smaller one in, and hope for the best. 

Medium-sized river in Colorado
Fly fishing a medium-sized river in Colorado

Medium Rivers

I throw Woolly Buggers in medium-sized rivers ranging from size 4-12. Some of my biggest trout have come from only 15-30 feet wide rivers. As long as there are ample food sources and room for the fish to grow, you can find some giants willing to eat large Woolly Buggers. 

If I know I can catch trophies, I’ll start by throwing a size 4 or 6 into the deeper water or under cut banks. I like to test the waters to see if anything wants the big bugger. I’ll switch to a smaller pattern when I see flashes or get a couple of soft tugs and can’t hook into them. As soon as I switch, I usually get a few true strikes.  

Medium rivers are tricky because you don’t always know what size of fish you’ll find. Stay equipped with all different sizes, and you’ll eventually find what the fish want. 

Large river in Wyoming
Fly fishing a large river in Wyoming

Large Rivers

Large rivers are my favorite type of water to fish with Woolly Buggers. I do not hesitate to throw my size 2 or 4 buggers all day. I know the fish are willing to eat them. The food they eat throughout the day is at least the size of a 2 or 4 bugger, so it doesn’t shock them. 

If I’m not getting strikes in fishy areas, I’ll drop to a smaller pattern to see if I’m overwhelming the fish. If that’s the case, I have no problem throwing a size 6 or 8 into the pools and seams. 

However, big flies often mean big fish, so avoiding those bigger buggers on large water is hard. 

Danny standing in the shallow part of the lake in Northern Arizona fly fishing.
Fly fishing a lake in Northern Arizona


Lakes are always tricky when it comes to fly sizes. Many anglers think large flies are the way to go on lakes, but they succeed most when they start small and work towards something larger. 

I’ll start with a size 8 or 10 bugger and slowly work my way larger. If I move to deeper water or see a giant, I’ll switch sizes to see what works best. A size 4 or 6 bugger is about perfect when pursuing those giants in the lakes. 


Woolly Buggers are one of the best trout flies on the planet. The trout love them, and they’re a blast to use. You can swing them, dead drift them and full-on retrieve them. As soon as you find what method the trout want, you can catch fish on the same fly all day. Stay prepared with buggers ranging from size 0 to 12. Start with those smaller flies and work your way larger if you run into some fish ready for a big meal. 

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