Even before REI Co-op debuted its Trailmade Hydration Sling, my daypacks were languishing in my garage—and not because they were derelict or unusable. These are top-notch packs, culled from my decades of gear-reviewing and winnowed to the most comfortably functional options I’ve ever tested. My 25-liter Patagonia feels tailor-made to my torso, while the 40-liter Millet pack is wicked light yet supportive enough to pull off a minimalist overnight. My 30-liter Black Diamond is a masterpiece of efficient durability, and a couple of collapsible summit packs (like grocery sacks with shoulder straps) round out the assortment.

Yet I rarely reach for them anymore. Living in metropolitan Maine, most of my trail time takes place on smaller networks where hikes last 90 minutes or less. On these shorter walks, a full-on daypack seems like overkill, and I’d rather carry my water bottle by hand than fall victim to the lingering dampness of the sweaty-backed shirt after hiking with a pack. That’s why REI’s hydration sling, new for spring 2026, is such a gamechanger.

REI Co-op Trailmade Hydration Sling

$70 at REI

How Much Gear Can the REI Trailmade Sling Actually Hold?

The zippered, 4.5-liter main compartment is just big enough for a rain jacket, and a cinch-top exterior mesh pocket holds the included 24-ounce Hydrapack water bottle. A small strip of webbing loops around the bottle’s cap and secures it in the pouch. In fact, carrying my beverage is pretty much all this sling aspires to do.

Why is a Hydration Sling Better Than a Traditional Daypack?

Apparently, I’m not the only one hiking with scarcely more than that. Jon Almquist, product manager for REI Co-op Brands, described the rise of a “new school” hiker that doesn’t load the Ten Essentials into a bulky daypack. “The conventional advice to ‘Be Prepared’ has served us well, but it includes lots of gear and preparation,” he explains.

New schoolers take a more casual approach. “You see them out there in tennis shoes, with maybe a water bottle in hand, and if you’re lucky, some snacks,” Almquist continues. REI wanted to develop a more comfortable carry solution for this increasingly common scenario. I’d say the Trailmade sling does exactly that.

How Does the Trailmade Sling Perform on the Trail?

On a 2.5-mile loop through Devil’s Back in Harpswell, Maine, I toted a full 24-ounce bottle of water, a rain jacket, car keys (clipped to the key fob inside the sling), and a battery pack for my smartphone (a search and rescue essential, even during short hikes). The ventilated padding on the shoulder strap and backpanel comfortably distributed weight.

So far, I’ve enjoyed the way the sling unburdens my pockets. The mesh sleeve on the strap holds my smartphone or a pair of sunglasses (pro tip: keep them in a cloth bag if you’re precious about scratched lenses). You can change the strap’s orientation so it can be worn over either shoulder. My fingers appreciate the release from cap-gripping duty (which gets tiresome after a while). The sling does have a tendency to make my shirt ride up periodically, but an occasional tug smooths things out. And it’s nice to have the option of stuffing a jacket (or swim towel, or charcuterie kit, or sunscreen) in the sling for use along the way.

Bottom Line: When Should You Use the REI Trailmade Sling?

I still use my daypacks when mileage leads me farther from the car, and when hike duration or elevation gain is big enough to include significant changes in weather. But for less ambitious walks, I’m sold on the REI Trailmade Sling.