Price: £140
Weight: 1.02kg
Sizes: S/M, M/L
TL;DR Review
A brilliant backpack for skiing, and for ski-mo style, fast and light touring ascents in particular.
Osprey Firn 18 Backpack Review
US brand Osprey’s roots stretch back to 1974, when a young Mike Pfotenhauer began selling handmade backpacks from his front room at the age of just 16. Growing up, he’d become frustrated by the build quality of the packs he used for weekend trips in the wilds of Oregon, and having learned how to sew from his mum, started making his own.
A move to Santa Cruz, California, and then Colorado helped him build the business. Before long he had handed over production to a group of local Navajo native Americans, whose sewing skills far outstripped his own. Over the years, the company pioneered many of the features that are now seen as standard on mountaineering, hiking and ski touring backpacks, like this one.
Osprey was sold to a larger parent company in 2021, and much of its production now takes place in Vietnam, but the company continues its relationship with members of the Navajo nation to this day, and Pfotenhauer himself is still involved as a senior designer.
Who is the Osprey Firn 18 aimed at?
The Firn 18 is designed for ski touring, and more specifically for ski mountaineering. As the name suggests, ski mountaineering prioritises moving uphill efficiently and tricky, technical ascents over downhill shredding. Ski mountaineering (or “ski-mo”) enthusiasts will often be carrying ice axes and crampons, and participants tend to use skinny, lightweight skis instead of the wide-waisted fat skis preferred by many backcountry enthusiasts. Weight is at a premium.
In recent years, ski-mo has become a competitive discipline, with participants racing against the clock. It will be included in the Olympics for the first time at next winter’s Milano-Cortina 2026 games. If backcountry skiing is the winter equivalent of enduro mountain biking, then ski mo enthusiasts are more like cyclo-cross riders. A lot of them even wear lycra.
Named after the state that compacted snow reaches just before it hardens into glacial ice, the Firn 18 is packed with features designed to make their life easier—and, most importantly, help them shave valuable seconds off their changeover times.
Osprey Firn 18 Style, Fit and Features:
The 18 litres of carry space on the Firn 18 is divided into three. There’s a main compartment that opens right up, with deep zips running round three sides. There’s a secondary pocket with dividers for your avalanche probe, shovel and essential safety gear, and then there’s a third, tube-like pocket accessible on the right hand side specifically designed so you can stash skins and crampons without ever removing the bag from your back.
If you’re racing, this would help save time, but it’s also a safety feature. You don’t have to be in a secure spot with space to place a backpack when removing crampons. The shoulder straps look a lot like those on a trail running vest—they’re wide, with pockets designed for a soft flask on one side, and a GPS unit, head torch, or phone on the other, allowing you to grab these essentials on the go.
“The waist strap is minimal, to save on weight”
The waist strap is minimal, to save on weight, and if you can take out the rigid back protector which reinforces the back panel to reduce weight still further. The Firn 18 weighs just over a kilo when empty, which is super light by any standards. The clips are designed to be operated with gloves and there are multiple gear loops.
Perhaps the main feature worth shouting about however, is the innovative ski lasso. When used with the adjustable ski loops at the bottom of the bag, this allows you to strap your skis together and swing them onto your back without ever removing the bag.
Osprey Firn 18 Materials & Their Meaning:
Osprey prides itself on its environmental, social and governance (ESG) standards. The materials used in the Firn 18 ski mountaineering pack contain recycled elements, and all of them meet the independently-assessed BlueSign standard, meaning they meet stringent criteria on environmental impact and workplace standards.
The water-repellent DWR coating used on the pack is free of PFC “forever chemicals”.
Osprey Firn 18 - Tester’s Verdict:
“I tested this on a solo mish at the start of the 24-25 season in San Martino di Castrozza, in the Dolomites. Appropriately enough, it was the morning after the Piolet d’Or (or 'golden ice axe') awards, commonly known as ‘the Oscars of mountaineering.’”
“High-speed, ski-mo style touring is not my usual modus operandi in the backcountry. I tend to prefer a relaxed skin up and a sit down with a sandwich at the top, so I’d never really tried an ultralight backpack like this before. I have to say, I was seriously impressed. The running vest style chest pockets were super useful, and although I thought the waist belt would be a bit thin, it was absolutely fine for packing light."
“I can see myself reaching for the Firn 18 in future just for sheer convenience”
“As a carry capacity, 18L is more than enough for your average day in the backcountry, and the layout of the pack’s interior made everything easy to find. The ski lasso—the pack’s signature feature—took a wee while to work out, but once I’d got it it was super easy to use."
“While I’m not particularly fussed about shaving milliseconds off my climbing times, I can see myself reaching for the Firn 18 in future just for sheer convenience. And for anyone who’s seriously into ski-mo, especially the racing side of the discipline, this would be the absolute perfect pack.”
You can find out more and buy the Firn 18 at Osprey.com
