You can do the river on your own, providing you get a permit. Only a certain number are issued each year. Better yet to go with an established outfitter. The river is not unchallenging at all in terms of rapids, either. Unless you are an experienced river runner and prepared to take on the 80 some odd rapids the river has to offer, and are willing to take the time to scout each major rapid, you are better off with an outfitter. This is definitely the kind of river that is best served by floating the first time with an experienced guide. Season runs typically from July through September.
Most of the licensed commercial outfitters here are not focusing exclusively on the fishing. The river is such a full scope recreational hit that many people run it for its own sake, with the fishing as a pleasant diversion. Middle Fork Wilderness Outfitters do have exceptionally knowledgeable fishermen among their ranks and devote several trips each year to a fly fishing theme.
The trout in this area spawn mostly in the spring, May through June in the tributaries, but it is likely to be the middle of July before you get on the river anyway. Water levels are quite high early in the season and better fishing conditions develop as the level drops. The Salmon Fly hatch comes off later here than other western streams; by the time you've got a comfortable water level to float, you'll probably be picking Pteronarcys off your sunburned neck.
The mayfly hatches seem to be scattered over the course of a rather short mountain season. We saw some stately green and gray drakes but nothing in fishable quantities. Blue winged olives and sulfurs were the most evident. Blue wings were better a little earlier or later in the day, with sulfurs or Pink Alberts, emerging more in the middle.
Caddis come on by mid summer and offer evening action, usually out of camp. Green, yellow and tan, mostly, in standard sizes. But it is the grass-hopper that carries the day throughout the heart of the season.
Middle Fork hoppers come predominantly in tan, yellow, and light olive. While any one of these may do the trick, I would have all three colors in my book.
The Parachute Hopper, as mentioned, seems to be not only the fisherman's favorite but the fish's as well. I fished my high floating Sofa Pillows and Stimulators effectively as well.
The nymph or larva dropper suspended 12 to 18 inches from a big dry is a popular and very effective tactic. You can vary the combo to match the emergence of the specie, mayfly or caddis. I've always liked the concept of a dropper and this particular combination has a lot of scope.
What to bring
The Middle Fork experience does not require much in the way of specialized fly tackle or technique. Your favorite trout rods in #3 to #6 weight will work fine. Tippets of 8 to 10 ft from 4X to 6X. Most of the fishing is from a boat or raft and a long rod is an advantage. You'll want waders if you plan to fish out of a boat.
Your outfitter will provide a complete trip list of equipment, clothing and gear, but be prepared for cool evenings and possibly days, more likely warm to hot days and cool nights though, depending on time of year. Thunder storms are fairly common and rain is always a possibility. Pack accordingly.
Middle Fork Wilderness Outfitters
Transport and shuttle
McCall Air Taxi
River Rat Shuttle
Lost River Outfitters
Silver Creek Outfitters
Idaho Country Inn
Current fishing regs
Idaho Dept. of Fish and Game
General info on lodging and services
Sun Valley/Ketchum Chamber of Commerce
Salmon Chamber of Commerce
Current list of guides and outfitters serving the Middle Fork
Idaho Outfitters and Guides Association
River permits & current river regs
Middle Fork River Ranger