REI Flash 18 Review: A Lightweight Daypack That Still Earns a Place in My Gear Closet
Some gear gets replaced after a season or two. Other pieces quietly become staples because they do exactly what you need them to do. The REI Flash 18 falls into that second category for me.
I actually bought this pack on a whim. It was an REI Member Exclusive, I liked the color, and the price was hard to pass up. As someone who has accumulated more backpacks than I probably need, adding one more seemed perfectly reasonable.
What I didn't expect was how often I'd end up using it.
The Flash 18 has become my go-to pack for short hikes, beach walks, campground exploring, and any outing where I don't need to carry a lot of gear. It also packs down surprisingly small, so it easily disappears inside one of my larger backpacks when I'm camping or traveling.
What Fits Inside?
The first time I used the Flash 18, I packed:
A lightweight sweatshirt
Small flashlight
Pocket knife
First aid kit, EpiPen, inhaler, and medications
Compact film camera
Extra roll of film
Snack
32-ounce water bottle
Even with all of that, there was still room left over.
Because the load stayed relatively light, the pack carried comfortably throughout a four-mile hike. Since then, it's been to the beach several times and on countless short day hikes where I wanted something simple instead of hauling a larger backpack.
Features
The Flash 18 keeps things intentionally simple.
The lightly padded back panel helps prevent oddly shaped gear from poking through while still keeping the pack extremely lightweight.
The shoulder straps are breathable, lightly padded, and surprisingly comfortable considering how minimal they are.
The main compartment uses a drawstring closure covered by a small top flap.
There's an internal sleeve for a hydration reservoir with an opening for the drinking tube.
Inside you'll also find a small zippered mesh pocket that's perfect for a phone, wallet, keys, or other small essentials.
The outside of the pack is intentionally clean, with daisy chains for attaching extra gear but no exterior pockets.
The removable sternum strap includes an emergency whistle, and the simple removable hip belt helps stabilize the load without adding much weight.
What I Love
The biggest strength of the Flash 18 is its versatility.
It's incredibly lightweight and comfortable when carrying smaller loads, which makes it an easy choice for short hikes and everyday adventures.
Because it packs down so small, it's also an excellent companion for backpacking trips. I can throw it inside a larger pack and use it around camp or for short side hikes without carrying another full-size backpack.
The simple design also makes it useful beyond hiking. I've used it for beach trips, sightseeing, and even as an extra travel bag when I needed a little more carrying capacity.
It's one of the more affordable technical daypacks available. Mine cost $35 when I purchased it, although current pricing has changed over the years.
What I Don't Love
The drawstring opening works well enough, but the small top flap doesn't provide as much protection from rain as a traditional lid or roll-top closure. Living in Southern California, that hasn't been much of an issue for me, but hikers in wetter climates may want to keep a small pack cover or dry bag handy.
The lack of exterior pockets is another tradeoff. I generally like having a water bottle pocket that's easy to reach while hiking. With the Flash 18, everything stays inside the main compartment.
Final Thoughts
The Flash 18 isn't designed to replace a full-featured daypack. It's designed to be simple, lightweight, and easy to take almost anywhere.
If you're looking for a pack for shorter hikes, travel, campground use, or as a lightweight companion inside a larger backpack, it's hard to argue with what the Flash 18 offers. The design has evolved since I bought mine, but the idea behind the pack remains the same: carry only what you need and keep the weight to a minimum.
Note: This review is based on the version of the REI Flash 18 that I purchased. REI has updated the design over the years, so some features may differ on the current model.
