Six Moon Designs Swift X Ultralight Backpack Review

This winter, I’ve been able to test the Swift X Ultralight Backpack from Six Moon Designs to see how it performs as part of my setup during multi-day adventures and day hikes. Designed for hikers and thru-hikers who value every ounce saved, the Swift X Ultralight Backpack blends streamlined design with robust durability, making it a compelling choice for those who want to travel light without sacrificing functionality.

One small feature I really liked: The Y-strap at the top can clip to the bag at attachment points both behind the mesh pocket and on top of it. This lets you keep the mesh pocket fully accessible, or gives you a way to secure anything inside the mesh pocket by securing the top.

Six Moon Designs Swift X Ultralight Backpack At a Glance

MSRP: Starting from $350.00​ (depends on harness and material choices)

Weight: Approximately 27 oz (765 g) in a frameless setup with pack bag and shoulder straps; up to 40 oz (1.1 kg) with additional configurations​

Capacity: Total volume of 56 liters (41L main body, 10L extension collar, 5L exterior pockets)

Materials: Available in Liteskin LS21 (gray), Ultra 200 X (black), or X-Pac VX21 (blue, black, coyote brown), all known for their durability and water-resistant properties

Intended Use

The Swift X is designed for backpackers and thru-hikers who prioritize a lightweight yet durable pack while seeking a pack with features such as load lifters and an internal frame. Its customizable features cater to individuals seeking a tailored fit and functionality, making it suitable for both short overnight trips and extended thru-hikes.

While this pack fits perfectly into an ultralight setup, it can accommodate weights up to an advertised 35 pounds (but can likely carry more) with ease, making it a reasonable choice for those not seeking the ultralight lifestyle.

The pack comes with an integrated, comfortable hip belt with large, built-in pockets.

Circumstances of Review

This review is based on experiences during winter hikes and backpacking trips in Colorado, where the Swift X was subjected to cold temperatures, snow, and varying trail conditions. I carried everything in it from a tent and quilt to my skis and snowshoes strapped to the outside. 

Features

A standout of the Swift X, to me, is the sheer amount of fun features SMD has managed to condense into a relatively lightweight pack.

Customizable Harness System: Users can choose between standard shoulder straps, a vest-style harness, or S-curve straps, allowing for personalized comfort and weight distribution.

Specifically, S-curve straps tend to fit much better on women, and I really prioritize finding a bag with this harness type. If you’ve never used a pack with anything but standard shoulder straps and experience any shoulder, neck, or back pain while hiking, give an S-curve strap a try.​

Adjustable Torso Length: The pack offers an adjustable torso length, accommodating various body sizes and ensuring a proper fit. Instructions come with the pack, making this easy to do at home.

The pack also comes with two phone pockets on the shoulder straps that, for the FIRST TIME I’VE EVER SEEN, are the right size, shape, and placement on the strap to actually be useful!!

Roll-Top Closure with Y-Strap: The roll-top design, complemented by a Y-strap, allows for secure compression and the ability to carry additional gear on top. The Y-strap, in particular, is important to me as it lets me comfortably carry a BearVault or my tent on the top of the pack without any slipping and sliding.

Storage Options: Features a large front mesh pocket and side pockets, providing ample space for quick-access items and gear organization. There is also a small pocket against the back inside the pack, letting you separate out the odds and ends that you want easy access to (e.g., glasses case, toiletries, first aid kit, spoon…).​

Optional Frame Stay: An optional Delrin stay can be added for enhanced load support, increasing the pack’s versatility for carrying heavier loads. ​The pack also comes with load lifters, allowing the back of the pack to curve against your body naturally.

Durable Materials: Constructed from either Liteskin or X-Pac fabrics, both offering excellent durability and water resistance, suitable for harsh weather conditions. ​While I hesitate to ever say a pack is actually waterproof and would always suggest a liner of some kind, this pack is water-resistant enough to withstand a light mist without concerning me.

Usage

In the field, the Swift X impressed me with its balance of lightweight design and robust functionality. It excelled in packability and provided quick, easy access to gear, which was essential on fast-paced winter hikes. Adjusting the harness and hip belt ensured a secure, comfortable fit, even on steep ascents.

Despite the minimalist design, the pack offered enough storage for multi-day trips and didn’t require me to give a ton of thought to packing to make my gear fit.

I was able to load this pack up with my traditional winter kit and strap my snowshoes and ice axe to the outside with very little trouble.

Six Moon Designs Swift X Pros

Highly Customizable and Fit Me Well: With multiple harness options — including traditional shoulder, vest, and S-Curve — and adjustable torso lengths plus removable hip belts, you can tailor the fit precisely to your body, ensuring optimal comfort and stability on the trail. The hipbelt can be very large but also cinch much tighter than hip belts on other brands, which I know is an issue for some hikers.

Durable & Weather-Resistant: Constructed from premium materials like Liteskin LS21 or X-Pac VX21, this backpack stands up to rugged, wet conditions. Reinforced stress points and a water-resistant build ensure reliability, even in harsh backcountry weather. I’m not calling it waterproof … quite.

The roll top can clip together at the top or attach to clips down by the water bottle pockets, depending on the look you’re going for.

Efficient Organization: Thoughtful design features, including deep interior pockets, external stretch pockets, and strategic attachment points, keep essentials like water bottles, maps, and snacks within easy reach without needing to unload the entire pack.

Easy to Tighten Hipbelt: The hipbelt adjusts quickly and securely, effectively transferring load to your hips. This minimizes unwanted movement and enhances stability, reducing shoulder and back strain on uneven terrain. Instead of pulling out to tighten, you pull it in. It seems like such a small thing, but it allows me to tighten the belt with one hand instead of needing both.

It’s easy to tighten the hipbelt with one hand!

Many Insertion Points for the Sternum Strap: Multiple attachment options for the sternum strap allow for fine-tuning the pack’s suspension system, reducing sway and bounce for a more secure and comfortable ride during dynamic activities. This also helps the pack fit better for hikers with breasts, as you have many options of where that sternum strap is going to fall on your body.

Six Moon Designs Swift X Cons

Price Point: At around $350, the Swift X is a premium investment. Its advanced features and durability come at a cost that may not suit every budget, especially for those new to backpacking. While this is a wonderful pack, I’d recommend beginners start elsewhere (cheaper) to get an idea of what they want from a pack and the rest of their gear before committing to this expense. 

Heavy for an Ultralight Setup: Despite its efficient design, you may find the Swift X slightly heavier than other minimalist packs. The robust materials and added features, while beneficial for durability and functionality, may increase overall weight for those seeking the absolute lightest load.

Would I Recommend This Pack?

Absolutely. For backpackers and thru-hikers who prioritize lightweight gear without sacrificing durability or functionality, the Swift X Ultralight Backpack is a standout choice. Its customizable fit and efficient design make it ideal for both fast, minimalist trips and longer backcountry adventures, especially in demanding winter conditions.

This pack is wonderfully comfortable and practical.

I wouldn’t necessarily call it ultralight, but Six Moon Designs does a wonderful job blending a surplus of features into a pack that could in no world be called heavy.

If you read my review of the Gossamer Gear Mariposa, I said that it was a perfect pack if only it were constructed out of material that held up better in bad weather. The Swift X is that pack, and I would strongly recommend it for any thru-hiker looking for a comfortable, well-fitting, highly-featured pack with an internal frame and load lifters. 

Shop the Six Moon Designs Swift X

Comparable Products

Gossamer Gear Mariposa

MSRP: $379
Capacity: 42 Liters
Weight: 1.8 lbs (29 oz)

Zpacks Arc Blast

MSRP: $349
Capacity: 45 Liters
Weight: 1.0 lb (16 oz)

The Six Moon Designs Swift X Ultralight Backpack was donated for the purpose of review.