The Atom is the smallest and lightest backpack offered by the UK’s Atom Packs. It is a specialized tool aimed at the fast and light hiker. The pack is highly customizable as Atom offers a range of choices in material and features.

The Atom is available in several volumes – all small (30L, 35L, and 40L) – and comes equipped without a frame or hipbelt in the standard configuration. Rather than prioritize load carrying, the Atom keeps the product weight low and focuses on usability with a variety of fast access features and pockets. The Atom is clearly designed as a companion for ultralight high mileage hikers.

Atom Pack
Source: Atom Packs

Features and Specifications

Embracing minimalism, I opted for the Atom in the smallest 30L size with a large torso.

  • Listed Weight: 360g (12.7 oz)
  • Measured Weight: 417 g (14.7 oz); Note: some, but not all, of the difference between listed and measured weight, can be found in the customizations I ordered in the pack. Mine had one shoulder strap pocket added (+13g, 0.5oz) and bound internal seams (+12g, 0.4oz)

I also opted for the VX21 fabric for the back panel rather than 500D Cordura nylon to increase waterproofness, which shaves 14g (0.5oz).

As I mentioned, the pack is fully customizable, but for the purposes of this test, I went with the standard configuration: two side pockets, two shoulder strap pockets, no hipbelt, and a bottom snack pocket with a trash port. The Atom also has a stretch mesh front pocket, haul loop, and a roll top (which clips to itself but does not strap down at the sides).


My first impressions of the Atom were dominated by how diminutive it is. You need to have a highly refined kit to get more than a day’s worth of food in the 30L Atom. I can fit three to four days worth of food in the pack while running with a base weight kit of about six pounds. A more typical but still ultralight and compact solo kit allows about two days of food, while a bulky kit barely allows for food at all. The pack is at its best with a seven to eight-pound kit, two days of food and Tenkara fishing rod tucked along for a weekend of wandering.

My initial impressions of quality are favorable. The pack passes my “quick quality” test, which is to ask “is it nicer than something I could sew myself?” I found a wiggle here and there on close inspection of the seams, but overall it’s put together well. The internal seams are bound and have a sturdy and professional look and feel.

Once on the trail, it’s obvious that the shoulder straps are well-designed. They have an S-curve shape that hugs the shoulders well and ensures the pack stays in place, although I still value the sternum strap for stability when jumping over trees and other technical maneuvers. For this same reason, I wish I’d added the optional webbing hipbelt. I’m happy to carry 15 – 20 lbs on my shoulders, but a webbing belt would be valuable to keep the pack stable during those times when I’m scrambling over boulders or bending to tie my shoes.

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S-shaped shoulder straps offer a secure fit.

The shoulder strap pockets are a treat. They are sized well for items like a phone, GPS unit, or snacks. The pockets hold these items securely while remaining accessible. Atom Packs took a bit of a design gamble with a basic fixed elastic opening, but they judged well, and the result is a simple, easy to use pocket (no fiddling to cinch and uncinch it). The upper size limit for these pockets is my Nikon W300 camera, which is a little larger than many point-and-shoot cameras and just squeezes in. The side pockets are of average construction. They work fine but are hard to reach – they sit a bit high as the pack is shorter than average.

The bottom pocket is a revelation in pouch convenience. It works well for any item that is too large for the shoulder or hip belt pockets but needs to remain handy. You can stash food, windshirts, and maps here and retrieve them rapidly. The trash port into the back of this pocket is also a smart touch. It’s a bit hard to find when reaching blind, but this improves with use, and it’s a nice secure place to store trash on the go. While handy, the use of stretch mesh on the bottom of the pack is a trade-off between durability and convenience. It’s another example of how specialized this pack is – well suited for light hikers who take care of their gear and push big miles, but not a good fit for folks that favor heavier gear or are hard on packs.

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Less ideal uses include multi-pitch trad climbing…
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…and ski mountaineering.

Compared To

The closest competitor to the Atom is the Simple V2 pack from Palante. The Simple V2 offers a similar feature set including a bottom mesh pocket, but the Atom has the advantage of being a bit lower-priced and fully customizable. If you’re experienced with packs this light, and you know what you want, the Atom provides the opportunity to get exactly that.

Other packs worth comparing to are the Katabatic Knik (42L, +14 oz), Zpacks Nero (30L, +11 oz) and Flow Pack (35L, +10 oz) from Little River Packs. Generally speaking, the Atom stands out by offering more refined construction and full customization.

Closing Comments

The Atom is a pack for hikers who have their gear pared down to a minimum, and a fastpacking hiking style that matches the pack’s focus on minimal loads and quick access to essentials. It will be interesting to see how well the weight vs. durability trade-offs (like the mesh bottom pocket) hold up after substantial miles. Durability and usability on high-mileage treks with a minimal kit will be the focus of my longer-term review of this pack, which will be published here later this year.

Where to Buy

Related Content

  • We reviewed another customizable pack from Atom Packs here.
  • Interested in ultimate customization? Learn how to make your own UL pack.


Product(s) discussed in this review were either acquired by Backpacking Light from a retailer or otherwise provided by the manufacturer at a discount/donation with no obligation to provide media coverage or a product review to the manufacturer(s). Some of the links in this article may be affiliate links. If you follow one of those links to a retailer’s website and subsequently make a purchase, we’ll receive a small commission on the sale, at no additional cost to you. This helps us create new content at Backpacking Light, and we greatly appreciate your support!

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