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Simms G4 Fishing Jacket Review


Simms G4 Pro Wading Jacket


3-layer GORE -TEX ® Pro Shell fabric. 100% Nylon face – 4.1 oz. in shoulders, 3.8 oz. in body
Heavier nylon face fabric in shoulders for additional durability and
lighter nylon face fabric in body for packability and breathability
YKK® center-front water -resistant zipper
2 Underarm YKK water-resistant zippers for fine-tuned ventilation
Bellowed chest pockets with hook & loop closure under storm flap
2 Zippered chest pockets featuring YKK ® thermolaminated water-resistant zippers with anti-corrosion sliders
New & improved adjustable storm hood
Patented built-in retractors
Tippet pockets feature Schoeller®-dynamic stretch fabric
Adjustable breathable stretch cuffs
Quick-drying, microfleece-lined hand warmer pockets
Large back pocket with vertical water-resistant YKK ® zipper
D-ring at center-back neck seam
Adjustable shock cord hem
‘Extreme Wet Weather’ construction
Sizes: S, M, L, XL, XXL

What’s the word…?

A protective all-weather outer shell always forms the framework of any layered, insulative system. Anytime you go outdoors, in cold, wind, or rain, you’re obviously going to be more comfortable protected from those elements. But throw in an ice cold steelhead river, driving sleet, and a two hour walk back to the car, and we’re talking about something a little more serious here. Serious outdoorsmen and serious fly fishermen need the finest protective clothing because they know from experience that their ability to perform in harsh conditions requires it, and sometimes their health, safety, and even outright survival, depend on it.

The Simms G4 Pro Wading Jacket is, arguably, the highest quality and most feature laden all-weather jacket ever made specifically for fly fishing. Superior construction, design, and the latest high tech breathable/ waterproof fabrics and materials contribute to its overall top notch performance and lasting durability.

Materials. . .

The main story in active outdoor rainwear is not a new story, but it’s still an important one. Micro porous fabrics, either Gore-Tex or various polyurethanes laminates, which are both waterproof AND breathable have been around for over twenty years. These multilayered fabrics keep the rain out but allow your perspiration escape to the outside, so you stay dry and comfortable, maximizing your performance when you need it. The Simms G4 Pro Wading Jacket is made from the latest generation top-of-the-line abric, Gore-Tex Pro Shell, which offers the ultimate in breathability, waterproofness, and durability over any other fabric. This “next generation” Gore-Tex Pro Shell is lighter and stronger due to a new woven backer fabric which slides easily over other layers and offers exceptional tear strength and internal abrasion resistance. The 4.1 ounce Pro Shell fabric is used in the shoulder area of this jacket for additional toughness, and 3.8 ounce Pro Shell forms the main body to increase overall breathability and reduce weight. A modern technological leap, from a design standpoint, is that all of the exterior zippers on the G4 (the full center zip, two underarm zips, vertical large back pocket zip, and the two chest pocket zips) are differing sizes of the new YKK thermo laminated water resistant zippers. These amazing zippers, built with anti-corrosion sliders, seal tight and will repel all water, except when fully submerged. The advantage is this eliminates the need for all of the exterior fabric plackets that would normally have to cover and protect old fashioned non-water resistant zippers on a waterproof jacket. Not only does this new arrangement save weight, it makes pocket access more convenient. In my experience, so far, the only down side to these new zips is that they don’t mate, nor slide as easily as softer, conventional zippers, but it’s a small price to pay, assuming that these new ones wear as long in the field as their forbearers.

Fit and Features…

When it’s dumping out, but the trout are still on the feed, it’s tough to get to your tools and tackle without getting everything else soaked. The G4 Pro takes that into consideration, and you’ll find three separate layers of pockets on each outer chest side to organize your gear; a lightweight dynamic stretch zippered tippet pocket, over a thermo zipped tackle pocket, over a large, bellowed top access pocket with a Velcro closure that can hold a fairly large fly box. So, all your terminal tackle can be handy in a downpour, as well as your nippers and forceps when they’re attached to the two built-in, foolproof Simms retractors mounted under fabric hoods alongside each pocket. You stay warm and dry inside.

The three most important factors often ignored, in my opinion, by many when selecting a rain jacket for fly fishing are:

a) Fit – Is the jacket sized properly to comfortably fit over the heaviest insulated layered clothing you can imagine wearing in the field? If you’re going to be fishing the Bighorn out of a drift boat in March, or plan on steelheading during the Northwest winter, you may be wearing three layers of fleece! If in doubt, go to the next size larger jacket. The G4 jacket was designed to be the top-of-the-line by folks that live and fish in Montana, so it’s already cut to accommodate multiple layers of insulation, and to allow a much greater range of motion in your shoulders and arms when casting and clambering around astream.

b) Proper wrist seals – Mountain climbers and fly fisherman, reaching and casting, spend a lot of time with raised hands. In the heavy rain, for any length of time while fly fishing you will experience water seeping down your arm, onto your torso, and eventually down into your waders, unless you have effective, adjustable wrist seals. Little pieces of elastic are simply not going to do the job. If you’ve had this happen to you only once, on a miserable day, you’ll reach for the best jacket you can buy. The Simms G4 has micro adjustable, breathable stretch cuffs that are supremely comfortable all day long and form a very effective water seal.

c) Ventilation – It’s great to start with Gore-Tex Pro Shell, the most breathable waterproof fabric going. But even the highest performance fabrics are unable to move all the moisture away from your skin when your core temperature rises, and you start to overheat. This usually happens during periods of extra exertion, say, hiking up the trail out of the river canyon at the end of the day. Sure, if it’s only sprinkling, you can open the front collar and cuffs of your rain jacket to dump some of your extra heat, but what if it’s coming down hard? The G4 is equipped with underarm ventilation zippers, a feature originated on the finest mountaineering jackets and, now, unique to the world of fly fishing in the G4. These YKK water resistant ‘pit’ zips can be opened by differing amounts, even in rain, to fine tune your core temperature while active. This is the only Simms jacket with this feature.

Company Profile … Warranty

Here’s what Simms says about their warranty;

“At Simms, we stand behind everything we make. If your Simms product fails due to workmanship or material defect during the life of the product, please return it to us for repair or replacement. This warranty does not cover damages caused by improper care, accidents or the natural breakdown of materials over extended use and time. All defective or damaged products should be returned to Simms for evaluation and will be repaired or replaced at the discretion of Simms Fishing Products.”

Simms was the pioneer in the fly fishing world, creating the first waterproof/ breathable Gore-Tex waders in 1993. Since then, they have successfully grown to become the largest domestic supplier of waders, boots, and fly fishing clothing in the fly fishing industry. Simms is one of only three manufacturers worldwide licensed to make Gore-Tex waders, and the only one that does so in the United States. Simms’ staff is largely comprised of committed anglers and they’re located in the heart of trout country; Bozeman, Montana. In a continuing effort to improve their products, at any given time, Simms has two to three hundred prototypes being tested in the field by professional male and female fishing guides, and other outdoor professionals. I can’t think of many other manufacturers that are that dedicated to getting things right. On this success, so far, I would guess that Simms will be around to back their warranties for a long time.

Overall Rating . . . 4 1/2 Stars out of 5

Superior, proven performance fabrics and materials, outdoor professional designed, with high quality workmanship and warranty, the Simms G4 is the “mountaineering standard” all-weather shell for the active fly fisherman, including fly fishing specific pockets, underarms zippers and tool holders. The G4 is awarded Gore’s highest “Extreme Wet Weather Rating”. This is, arguably, the finest example of durable, functional fly fishing all-weather wear available, at any price.


Made from the highest performance Gore-Tex Pro Shell fabric, coupled with breathable, adjustable stretch seal cuffs, and next-generation YKK water resistant zippers, including underarm zippers for fine-tuning core temperature when exertion levels go up. Quick drying micro-fleece handwarmer pockets, built-in retractors, and plenty of tippet/accessory pockets.


Bells and whistles can add function, but increase the weight, and cost, over a basic wading jacket.

Bottom Line

Beautifully constructed all-weather wading jacket with technical features found, previously, only in the highest quality mountaineering shells. The only Simms jacket using Pro Shell, with Gore’s Extreme Wet Weather rating. Adjustable storm hood protects vision in nasty weather, and pit zips rock when hiking!

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