Osprey Stratos 24/Sirrus 24 Daypack Review

Bottom Line

The Osprey Stratos 24 (men’s) and Sirrus 24 (women’s) stand out for their highly ventilated back panels, fully featured designs, and supportive harnesses, which make heavier loads feel lighter on your back.

A big reason why the Stratos and Sirrus are perennial bestsellers is Osprey’s ventilated AirSpeed back panel. Do you hate back sweat? The AirSpeed’s suspended mesh allows for airflow between your back and the pack.

You’d be hard-pressed to find a more supportive and comfortable option in our best hiking daypacks gear guide – at least when you’re carrying extra water or gear. At the same time, the average day hiker doesn’t carry enough weight or hike far enough to benefit much from this pack’s supportive harness and generous padding. 

In many cases, the Osprey Stratos/Sirrus may be too much pack for beginners, casual hikers, and (especially) minimalists. It’s a comparatively heavy daypack with more features and backbone than most hikers need. However, if you prefer a traditional daypack that prioritizes comfort and support over weight savings, we recommend the Osprey Stratos and Sirrus for more serious and gear-intensive day hikes. 

How We Tested

The CleverHiker team has years of experience testing the Stratos/Sirrus. Senior editor Ian Krammer has used this pack for three years, including several difficult summit hikes in Colorado. Gear analyst Jory Brass has owned a version of the Stratos since 2015. On top of hiking thousands of miles in this pack, he spent three months testing the latest version of the Stratos 24 side by side with ten other daypacks to compare their comfort, organization, support, and weight. 

Comfort

Generally speaking, the more weight you’re carrying, the more comfortable you’ll find the Osprey Stratos 24 and Sirrus 24.

For better or worse, this is one of the sturdiest daypacks we tested. The Stratos/Sirrus features an internal frame and weight-bearing hip fins to carry weight more comfortably than the average daypack. We’ve found the supportive harness a comfort plus when carrying several pounds of water, winter layers, food, or camera equipment. At the same time, these features can feel excessive if you’re not carrying much weight.

No matter what we’re carrying, we’re big fans of Osprey’s AirSpeed suspension system – a flexible mesh back panel that puts nearly two inches of air between your back and the pack. During our field tests, this off-the-back fit minimized sweat and prevented overheating. The airy back panel is a big reason why CleverHiker Editor Jory Brass has worn this pack for more than 10 years. 

The Stratos/Sirrus also features more padding along the shoulder straps and hipbelt than most daypacks, which often skimp on cushioning to shave weight. During our test hikes, we appreciated how the hipbelt and shoulder straps were softer and more ventilated than the cheap mesh ones on lighter and more casual designs. 

Fit also feeds into comfort. Here, the Stratos/Sirrus stands out in two ways. First, Osprey offers gender-specific fits: the Stratos for men and Sirrus for women. Second, the Stratos/Sirrus has an adjustable torso length. Notches in the back panel make it easy to shorten or lengthen the torso to match your body. 

This is the rare daypack that comfortably fit two very differently sized testers (one who is 5’6” and slender and another who is 200 lb. with a broad chest and shoulders). The sternum strap and load lifters further enhance the pack’s fit. 

Organization

Osprey’s fully featured daypack, the Stratos/Sirrus has plenty of purposeful pockets to keep you organized on the trail. During testing, we especially liked the two spacious hipbelt pockets, which made it easy to keep our phone at hand and snag our lip balm, energy gels, and headlamp on the go.

This pack features a spacious main compartment with plenty of room for winter layers, lunch, and extra gear like winter traction devices. On top, there’s a generous zippered mesh pocket with a key clip. In the field, we appreciated having a secure place for our keys and plenty of room for our wallet/cards, phone, passport, and other small items. 

It’s easy to overlook some of this pack’s organizational features, such as the built-in safety whistle and magnetic bite valve attachment on the sternum strap. Likewise, the included rain cover hides in a small zippered compartment near the bottom of the backpack.

We made some use of the center front pocket with the vertical zipper. It’s the right size to stuff a shed layer, map, or small camera. However, we didn’t find it as useful or accessible as the stretch-mesh shove-it pocket on other Osprey daypacks.

The Stratos/Sirrus features Osprey’s Stow-on-the-Go trekking pole attachment system. Simply slip your collapsed poles through the bungee at the bottom of the left shoulder strap basket-first until the baskets sit against the big plastic loop behind your left hip. Ian loves the convenience of this system. Jory sometimes uses the attachment but finds his trekking poles rub against his broader frame in this position.

The Stratos/Sirrus features an internal hydration sleeve that easily accommodates a 3-liter water reservoir (or less). There’s a hanging mesh pocket that somewhat gets in the way of the sleeve, but it’s still a functional space. 

The stretch-mesh bottle pockets are deeper than most daypacks and worked well with Smartwater bottles, Nalgenes, and even a large camera tripod or trekking poles. There are compression straps for keeping longer items like poles securely attached, although external attachment points are limited.

Support

Of all the daypacks we tested, the Osprey Statos/Sirrus and Gregory Zulu have the most supportive harnesses. When we field-tested fully loaded daypacks side by side, this pack carried weight better than the competition.

The Stratos is one of just a few daypacks on our list with a true internal frame – a thin wire skeleton that distributes weight evenly across the back while shifting the load down to the hipbelt. Unlike most daypacks on our list, this pack’s hipbelt actually carries weight. When we tested our fully loaded Stratos on the Embudito Trail, we clearly felt the brunt of our load sitting on our hips (where it should be) and off our neck and shoulders. 

In short, this is a great daypack for longer hikes where you’re carrying extra gear. CleverHiker’s Ian Krammer has done some of his longest, most difficult mountain climbs in the Stratos, including a 44-mile, 22-hour summer day in Colorado’s Sangre De Cristo Range. Similarly, analyst Jory Brass chooses the Stratos when he’s hauling extra water in the Southwest, hiking in winter with extra-bulky layers and an emergency bivy, or carrying a heavy camera and tripod while testing gear across New Mexico. 

Weight & Compressibility

The trade-off to all this support and comfort is weight. The Stratos 24 and Sirrus 24 tip the scales at 2 pounds, 15.2 ounces and 2 pounds, 13.8 ounces respectively. Plus, the pack’s internal frame means it won’t compress down into a more packable size. This backpack is meant to be worn on serious day hikes – not stuffed in a suitcase. 

When we tested fully loaded daypacks side by side, we felt the “lightweight” packs dragging down our shoulders and necks. They lacked robust harnesses to shift the load from our shoulders to our powerhouse: the hips. We didn’t notice that extra weight while wearing the Stratos. Its supportive harness shifted the load to our hips, where we barely felt it. 

The Stratos/Sirrus does have two sets of compression straps to slim it down a bit. However, it is not compressible compared to frameless daypacks. It doesn’t fold or roll away and won’t fit in other backpacks. If you’re looking for a lightweight option for shorter trips or a packable daypack for traveling, this is not it.

Should You Buy the Osprey Stratos 24/Sirrus 24?

The Osprey Stratos/Sirrus 24 is a standout for day hikers who value ventilation, comfort, adjustability, and support. This pack makes heavier loads feel lighter and includes tons of organizational features, including a rain cover that adds to all-around value. If you often carry a lot of gear and hike more than a couple hours, this is an ultra-comfortable and ultra-supportive option.

On the flip side, the Osprey Stratos/Sirrus makes less sense for casual hikers and those who rarely carry much weight on their backs. The average day hiker won’t benefit from the extra support and comfort – and might find the Stratos/Sirrus too heavy and structured for their hikes. This isn’t a daypack for minimalists or easy walks in the woods. It’s made for more hardcore hikes that require hauling additional water and gear.

What Other Hiking Daypacks Should You Consider?

If the Osprey Stratos/Sirrus doesn’t catch your eye, head over to our best hiking daypacks gear guide for more top picks.

Osprey Talon 22/Tempest 22 Review: These Osprey packs don’t have the off-the-back fit or included rain cover of the Stratos/Sirrus, but they’re more versatile, better balancing comfort, organization, and support with weight and packability.

Gregory Citro 24 H2O/Juno 24 H2O Review: These packs include one of our favorite hydration reservoirs on the market. They are every bit as comfy and easy to use as the Stratos and Sirrus – and they’re a better value if you want the water bladder.

Gregory Zulu 30 Review: For a similar daypack in both design and price, the Zulu is another fully featured option with a ventilated back panel, internal frame, supportive harness, and included rain cover.