The REI Co-op Trail 40 Pack offers easy access and organization for day hikes, overnights, and travel adventures. Perfect for all your outdoor needs 🌲

The REI Trail 40 backpack is a versatile and rugged pack designed for hiking, travel, and everyday use. With a 40L capacity, innovative features, and durable construction, this backpack is a great option for adventurers looking for one bag that can do it all. In this in-depth review, we’ll cover the key specs, pros and cons, and what makes the REI Trail 40 stand out.

Overview and Technical Specs

The REI Co-op Trail 40 pack is an internal frame backpack with a spring steel perimeter frame that provides excellent load support while allowing the back panel to conform to your torso. It has a 40L capacity, weighing in at just 3 lbs for the men’s medium and 3 lbs 1 oz for the large.

Here are the key specs and features:

  • Capacity: 40L
  • Weight: 3 lbs (M), 3 lbs 1oz (L)
  • Torso fit: Men’s – M: 17-19″, L: 18-20″; Women’s – M: 16-18”, L: 17-19”
  • Materials: Recycled ripstop nylon, recycled polyester lining
  • U-shaped panel opening with 4 zippers for easy gear access
  • Front stretch mesh pocket and side water bottle pockets
  • Trekking pole and ice axe loops
  • Internal hydration reservoir sleeve (reservoir not included)
  • Zippered top stash pocket and internal mesh pockets
  • Adjustable sternum strap and padded harness
  • Removable rain cover included

Hiking Performance and Comfort

With its innovative suspension system and ergonomic design, the Trail 40 is built for comfort on the trail. The perimeter frame transfers weight to the hipbelt while allowing flexibility, and the mesh back panel promotes airflow. The pack comes in gender-specific sizes with an adjustable harness and S-curved shoulder straps to provide a customized fit.

The hip belt and harness are generously padded for carrying heavier loads up to 30-35 lbs. Features like the sternum strap, load lifters, and stabilizer straps help you fine-tune the fit for all-day hiking comfort. The side water bottle pockets, stretch front stuff pocket, and daisy chains give you plenty of external storage options as well.

Travel-Friendly Design

In addition to its technical chops, the Trail 40 works great as an airplane carry-on and travel companion. The front panel U-zipper provides easy access to contents without unpacking the whole bag. Inside, features like the zippered top pocket, internal mesh pockets, and laptop/hydration sleeve help keep you organized.

The stowable harness and hip belt tuck behind a zippered panel to keep the pack streamlined for air or bus travel. At 22.5 x 13 x 10 inches, the Trail 40 fits in most overhead bins and under airplane seats when needed. The rugged recycled nylon stands up well to abusive baggage handlers too.

Storage and Organization

With 40L of capacity, the Trail 40 provides ample room for gear, clothing, and travel necessities. The U-shaped front panel opens wide for easy packing access, while the top lid and drawstring closure allow top loading. Inside the pack, you’ll find a zippered top pocket, a large expandable mesh pocket, and a hydration sleeve that can double as a laptop compartment.

On the exterior, the Trail 40 has two stretch mesh water bottle pockets, a long zippered pocket perfect for rain gear or layers, and daisy chains for lashing gear. There are also special loops for trekking poles and ice axes. The zippered hip belt pockets provide quick access to small items you need on the trail.

Durability and Construction

REI built the Trail 40 for the long haul with durable recycled ripstop nylon and hardy YKK zippers. The exterior fabric resists abrasion and repels moisture during rainy hikes. At the high-wear bottom, an extra layer of recycled nylon provides added toughness. The spring steel frame retains its shape even when overloaded, and the harness is robust enough for heavy loads.

Many reviewers praise the Trail 40’s durability even after years of heavy use. The 1-year REI warranty provides a nice added peace of mind too. With care, this pack should last for many seasons of travel and outdoor adventure.

Pros and Cons


  • Durable recycled ripstop nylon exterior
  • Versatile U-shaped panel access
  • Lightweight internal perimeter frame
  • Padded and ventilated back panel and harness
  • Trekking pole and ice axe attachments
  • Men’s and women’s specific fits
  • Carry-on sized for airplane travel


  • Zippered laptop sleeve lacks padding
  • No bottom zipper access
  • Several color options discontinued

Reviews and User Experiences – 5 Stars for the Trail 40

The REI Trail 40 earns rave reviews from outdoor enthusiasts, with many citing its versatility, durability, and comfort. This pack receives a 5-star overall rating based on hundreds of customer reviews.

Backpackers praise the Trail 40’s performance on multi-day hikes. With the supportive perimeter frame and adjustable harness, users report the pack feels great even when loaded down for overnight trips. They love how the suspension keeps weight centered on the hips during miles on the trail. Despite its technical design, the Trail 40 remains flexible and non-restrictive.

Travelers also give the Trail 40 high marks as a carry-on bag. Users say it easily fits in overhead bins and under airplane seats when fully packed. The stowable shoulder straps make the transition from trail to airport smooth. The U-shaped zipper makes items inside very accessible, while the multiple pockets keep essentials organized.

Overall, the consensus is the Trail 40 offers premium quality and features at an affordable price point. For those seeking a rugged yet comfortable do-it-all backpack for hiking and travel, the Trail 40 earns a 5-star recommendation.

Backpacking and Hiking Performance

With its innovative suspension and adjustable features, the Trail 40 provides outstanding performance on the trail. The perimeter frame transfers weight to the hips while allowing flexibility through the torso. This makes it comfortable for long miles with a heavy load.

The mesh back panel and ventilated padding help keep you cool and dry. The angled shoulder straps minimize chafing, and stability straps and trekking pole attachments allow you to fine-tune the fit. The Trail 40 works great for 2-4 day backpacking trips, carrying 30-40 pounds when needed.

The side stretch pockets fit water bottles and the belt pockets grant easy access to snacks and gadgets while moving. The daisy chains let you strap on extra gear, and the U-zipper makes accessing items inside simple. The Trail 40 has all the essentials for backcountry hiking and overnight adventures.

Top Traits for Travel

Frequent travelers praise the Trail 40’s convenient design and durable materials. The pack meets carry-on size limits for most airlines, letting you avoid baggage claim after long flights. When packed strategically, it can fit under airplane seats as well.

Inside, the laptop sleeve and organizer pockets keep your gadgets and personal items secure. The lockable zippers and hidden passport pocket provide peace of mind in crowded spaces. The ripstop nylon fabric holds up well to rough baggage handling when necessary.

The Bottom Line

For those seeking a backpack that can shift seamlessly from the airport to the trail, the REI Trail 40 is a top-tier choice. It provides excellent comfort and support for loaded days on the trail, and just enough features and organization for travel and urban use.

The Trail 40 may not satisfy ultralight hikers or hard-core travel pros, but it’s an ideal hybrid for those who enjoy few days hiking and being active on vacation. For only $129, REI delivers outstanding versatility and quality in a sub-3-lb package built to last.

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