REI Co-op Flash Hiking Boot Review


2 lbs. 3.9 oz. (men’s size 9)


Yes (HydroWall)

What we like:

Great price, unique knit upper, and lots of sustainability measures.

What we don’t

Middling comfort and traction.

Rating: (4.1/5)

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After a long hiatus, REI Co-op has returned to the hiking boot game with the Flash. Sharing a name with the brand’s in-house line of lightweight hiking and backpacking gear, the boot is highlighted by a unique knit upper, strong emphasis on sustainability with recycled materials used throughout, and a very competitive $130 price tag. In testing the Flash, we did have some complaints—namely, the traction is fairly disappointing, and we experienced pressure points along the inside ankle when laced tightly—but if you can get a good fit, it’s a competitive offering for day hikes and short overnight adventures. Below we break down the Flash’s performance. To see how it stacks up to the competition, check out our article on the best hiking boots.



As you slide your feet into REI Co-Op Flash it’s obvious that this isn’t your normal hiking shoe. The style has a sock feeling due to the gussets that stretch on the tongue and the upper reminds me of a running boot with the sensation of a surprisingly flexible. Underfoot, the inside of the shoe is a pleasant surprise. Unlike many stock models that are thin and cheap and thin, the TrailBed insole is fairly thick, has excellent arch support it also offers more cushioning and cushioning (it’s nearly rubber-like) as I’m accustomed too on top hiking shoes. I’m also convinced that REI have a good combination of stiffness and flexibility with the Flash It’s easy to walk pretty fast inside the boot, though there’s no smoothness like trails runner-inspired models such as Hoka One One’s latest Anacapa Mid. However, you’ll get the added protection and support on rough and rough terrain.

But that’s the only positive aspect of my experiences with Flash. Once I had tied them up I experienced major pressure points along the inside of my ankles that didn’t completely go away even though that the remainder of my boots were fitted. The cause is the combination of the thin padding around the collar and tongue, as well as an eyelet made of metal that is close to the collar and presses against the collar as your laces are tightened. The only method I could find to relieve this discomfort was loosening my laces which ultimately made the boots feel untrustworthy and untrustworthy. Because of its broad fit throughout, and the roominess around the heel, which caused friction when climbing steeply–I found myself merely dealing with the pressure points in order to keep from developing blisters and hot spots.


It’s advertised as a light-weight and fast-moving design My Flash boots Flash shoes in male size 9 measured 2 pounds 3.9 grams according to my own scale (they’re advertised as 2 pounds. 2 oz.). For day-hiking models, this figure is close to the average. The popular and more supported Merrell Moab 2 Mid WP weighs the same 2 pounds and 4 ounces. Keen’s Targhee III WP Mid weighs 2 pounds 2.8 pounds and 2.8 ounces. In addition, you can make the choice lighter by using slimmer models such as the Salomon X Ultra 4 Mid GTX (1 1 lb. 14 oz.). In all it’s a bit heavy. Flash isn’t heavy in any way however, it’s certainly not the superlight trail-running-inspired model that a lot of backpackers on the lookout for.


In general, hiking boots offer decent traction on many terrains, however I noticed that REI’s Co-op Flash did not perform as well on more rough and rocky terrain. In particular, the lugs are quite shallow, and they aren’t grippy and quickly cake up on areas with soft surfaces, like dirt. This is also reflected in lower grip, both in steep descents and climbs. It seems to me to be a simple solution: just increase a few millimeters your lug length especially under the heel for brakes and toes for steep inclines as well as slippery slopes. In fairness the boot did pretty in the rock terrain and the rubber isn’t susceptible to cracking or breaking off in a rough terrain. As long as no changes are implemented, traction is a problem that strikes me as an obvious weakness that the flash’s style.

Stability and Support

Sitting just over the ankle, the Flash doesn’t provide the same level of security as you get with a full-on backpacking boot like Salomon’s Quest 4 or Lowa’s Renegade. However, the mid-height design and decent stiffness underfoot should be plenty for most day hikes and moderate backpacking. The boot also has a pretty chunky and wide heel, and the lower stack height gives it a planted feel overall (your feet are fairly close to the ground). Finally, it’s worth noting that because of the aforementioned roomy fit in the heel and toe box, it was essential for me to keep the laces tight. For those with narrower feet, this extra space could potentially lead to a sloppier and less secure feel on more technical terrain.


As with most boots in the sub-$150 category, the REI Co-op Flash does not come with a Gore-Tex liner. Instead, you get a HydroWall-branded design, which uses 75-percent-recycled polyester and has proven to be a solid performer thus far in testing. I haven’t given the boot a proper soaking yet, but I experienced no issues or leakage when standing in a creek, and the knit upper material shed moisture surprisingly well (although I’d expect it to start absorbing after extended exposure). Based on the tongue design, you won’t want to step into water that rises higher than the bottom of your ankle, so there are undeniably limitations to the protection. But for light outdoor use, it just should be sufficient for most.


It’s always a choice to compromise breathability when you choose waterproof boots and the Flash isn’t an exception. The knit upper and budget-friendly waterproofing aren’t helping in the long run, and I ended up sweaty feet during hiking in the summer with temperatures in the mid to low 70s Fahrenheit. The reality is that every waterproof hiking shoes have some compromises in this regard, so it’s not a major issue. However, as with other designs that we’ve tried, we would prefer to see a nonwaterproof alternative released in the near coming years (the Flash is currently only available with the HydroWall membrane).

Toe and Ankle Protection

Looking a lot like a pair of trail running shoes, the Flash boasts a TPU overlay that runs the full length of the boot. This translates to a light amount of foot protection, including fairly solid cushioning at the toes (although it’s not as sturdy as a full rubber design) that continues all the way through the heel. And despite having only moderate levels of padding around the collar, I found ankle protection to be sufficient to take the sting out of light hits when squeezing in between rocks

Build Quality and Durability

With the ability to sell in-house, REI has an upper hand in value, so it’s not a big surprise the Flash boots are a solid deal. For $130, you get the high-quality knit upper and a build that is impressively stylish. And thus far in testing, it’s all holding up very nicely: the firm rubber outsole looks like it’ll have a long life (despite my previous complaints about its relatively limited grip), and all remaining pieces are looking good. My only complaints are that the lacing system has a tendency to loosen throughout the day, and from a comfort perspective, REI still has a long way to go to match the all-around performance of top brands like Merrell, Salomon, Asolo, and others.

Fit and Sizing

I wound up ordering my standard men’s size 9 with the Flash boot, and the overall fit struck me as a little big. Not only was it roomy in the toe box (a positive for most hiking trips), but the heel was also a bit too wide for my preference (I have a slightly narrow heel). This made it necessary for me to snug the laces pretty tightly, which seemed to exacerbate the previously noted problem with pressure points at the ankles. And lengthwise, I found the boot to run a little long as well. It’s not enough for me to recommend sizing down a half size, but those that are often on the fence will likely want to try the boot on in person to ensure the best all-around fit.


In short, we think that REI Co-op set a new standard in incorporating eco-friendly measures into the Flash’s design. Most of the boot’s makeup utilizes recycled materials, from the FirmaKnit upper (99% recycled PET polyester) to the HydroWall waterproof membrane (75% recycled polyester), TerraGrip tread (20% recycled rubber), TPU overlays (30% recycled), and polyester webbing and lacing. In addition, the midsole uses 10 percent algae-based foam, and the insole utilizes a 25 percent bio-based compound. Added up, it’s one of the most intentional hiking designs we’ve seen to date, and we applaud REI for the effort. 

Women’s Version of the REI Co-op Flash

We put the men’s Flash through its paces for this review, and REI also makes a nearly identical women’s model. The women’s REI Co-op Flash costs the same at $130 and boasts many of the same features, including HydroWall waterproofing, a knit upper, and lightly protective TPU overlays. In parsing out the differences, the women’s variation checks in a little lighter at 1 pound 13 ounces per pair and comes in a unique Smoke/Lilac colorway (in addition to the Granite Black and Bark/Moss options that are shared with the men’s boot). And as I touched on above, REI’s Flash collection also includes a range of lightweight hiking and backpacking gear, including backpacks, tents, trekking poles, a sleeping pad, and more.

What We Like

  • The Flash is strong value at $130, including a high-quality knit upper, impressively stylish build, and long-lasting rubber outsole.
  • TrailBed insole is decently thick, offers good arch support, and is noticeably better-cushioned and more comfortable than most stock designs.
  • Nice balance of flexibility and stiffness: it’s easy to move quickly, but you still get decent support and protection for rough and rocky terrain.
  • Strong focus on sustainability, including the use of recycled materials, bio-based compounds, and algae-based foam.

What We Don’t

  • I experienced significant pressure points along the inside of both ankles as a result of the thin collar and tongue padding and metal eyelet that digs in against the collar.
  • Outsole lugs are noticeably shallow and lack bite in softer surfaces like mud.
  • Fit is on the bigger side with a wide heel and longer-than-average length. 
  • Knit upper and budget-oriented waterproofing translate to subpar breathability in warmer temperatures (and the boot isn’t offered in a non-waterproof model).

Comparison Table

REI Co-op Flash $130 Lightweight 2 lb. 2 oz. Yes (HydroWall) Knit
Merrell Moab 2 Mid WP $135 Lightweight 2 lb. 4 oz. Yes (M Select) Leather / mesh
Keen Targhee III Mid $150 Lightweight 2 lb. 2.8 oz. Yes (Keen.Dry) Nubuck leather / textile
Salomon X Ultra 4 Mid GTX $165 Lightweight 1 lb. 14 oz. Yes (Gore-Tex) Leather / textile
Oboz Sawtooth II Mid $155 Light/midweight 2 lb. 6 oz. Yes (BDry) Nubuck leather / mesh
Altra Lone Peak ALL-WTHR $170 Lightweight 1 lb. 14 oz. Yes (eVent) Synthetic

The Competition

REI Co-op’s new Flash joins a crowded and competitive field of hiking boots built for day hiking and short overnights. Merrell’s Moab 2 Mid WP has similar intentions and is another popular offering in the budget category. Stacked up against the REI, the Moab is the classic choice with a more traditional look, secure fit, and excellent cushioning. On the flipside, the REI is the more modern offering and has a simpler and more streamlined build. Neither are high-performance models—both are best-suited for day hikers and shorter, on-trail backpacking trips—but given the pressure points at the ankles that I experienced with the Flash, the Moab strikes me as the superior design.

The next one next is the Keen Targhee III WP Mid like the Moab, is a favorite of long-term hikes and moderately-sized backpacking trips. Like the Merrell Keen, the Keen is a classic design and style, featuring a the leather upper, robust toe cap, and a spacious toe box. With a price tag of just 20 dollars more than the Flash and Targhee, the Targhee has more cushioning and a stronger design thanks to its leather upper. We didn’t encounter any major issues with comfort when compared to the Keen. The Targhee is quite expensive for a design that isn’t very appealing Therefore, we suggest price-conscious consumers stick with cheaper Moab above. On the other hand for those who prefer an ultra-light and agile boot would be better on this X Ultra below.

The comparison would not be complete without mentioning Salomon’s Ultra 4 Mid GTX that is among the most versatile all-around hiking boots that cost less than $200. It is, in essence, superior to the Flash in a lot of ways, excluding cost. Like I mentioned earlier it’s a more compact design that beats it’s Flash in weight by 1 pound 14 pounds, and also provides superior comfort on trails, protection in stability and support, and grip on a range of terrains (including harder and more rough terrains, where the Flash was unable to cope). If you’re able to afford the extra $35 cost We believe that the Salomon is by far the most versatile and well-rounded option.

Oboz is known for its shoes that are comfortable first, and their Sawtooth II Middle WP is a favorite choice for backpackers of all kinds. The Sawtooth is more expensive in weight and bulkier than Flash priced at 135 dollars and 2 pounds and 6 ounces, respectively however, you will get the more durable nubuck upper. The O Fit insoles are exceptionally comfortable, with excellent arch support and a comfortable soft. The fit is another plus In our testing, we observed that the Sawtooth was as comfortable as it was a glove. There were no areas that were loose, a tight heels, as well as a comfortable general feel. However, despite its average weight it was noticeable that the Sawtooth was noticeably heavy and heavy when on the trail. Also, the heavily cushioned midsole contributed to a less confident and a more connected experience than that you can get from the Flash. The end result is that the final decision will depend on the user’s preferences regarding the fit and comfort (the Oboz wins out) against stability, price and design (the REI gets the edge).

One final option is the Altra over-the-ankle model of their most popular trail runner called the Lone Peak ALL-WTHR Mid. At first glance it’s important to note this: the Lone Peak is a strikingly different style from the Flash in both its intentions as well as the way it’s presented. Even though the Flash is a good choice for day-hiking and backpacking with light weight however, the Altra is basically a strengthened trail running shoe designed for light and fast runners The Altra is lighter at just 1 pound 14 ounces it’s much more agile and agile than the REI however it does make some compromises with regards to protection and stability. If your primary objective is speedy ground cover and efficiently, these compromises–along with the price increase of $40 might be worth the cost. In other cases the Flash offers more appeal.

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