Trail Testing the First Packs From Big Agnes: ‘Sun Dog’ 45L Review

Behold: Big Agnes enters the ultralight pack space. We put one of its first models to the test.

The day has finally come. Big Agnes, purveyor of tents, camp chairs, sleeping bags, and pads — finally makes backpacks. Big Agnes announced he would venture into the pack space back in August 2021but they hadn’t hit shelves — until now.

We tested one in spring on several full-day hikes (5-11 miles) and a quick overnight on various trails in Colorado.

In short: For its first-ever packs, Big Agnes hit a home run. This women’s pack is lightweight, with a minimalist and functional design for anything from long technical junts to backpacking to thru-hikes. Most of all, we liked the Sun Dog’s design — rolltop and back panel access to the main compartment — and its adjustability and comfort on the trail. The price is also highly competitive for the ultralight pack market.

Big Agnes Sun Dog 45L Pack Review

A view of the hip belt design on the women’s Sun Dog 45L; (photo/Sean McCoy)

The women’s-fit Sun Dog 45L Pack (there are three other full-size packs, as well as two daypacks) is a top-loading bag with a roll-top design. Minimalist compression straps cinch down to secure your haul on both sides of the pack.

Internally, there’s a small sleeve for a bladder (up to 3 L) and routing for a hydration tube to the front of the pack. We made sure to test the pack with and without a bladder.

The Sun Dog 45L includes two color-matched 1.6L removable hip pockets for stashing small items (a wallet can fit!) and a “7L Trash Can” for camp trash and good LNT stewarding on trail stewarding.


  • Design: Women’s-specific fit, adjustable shoulder, hip belt, sternum, and load lifter straps
  • Size: One size; torso length 16-18 inches
  • Materials: Recycled Mipan regen ROBIC nylon, solution-dyed ripstop grid, reinforced twill fabric on the bottom for durability
  • Claimed weight: 2 lbs., 13 oz.
  • Verified weight: 3 lbs.
  • Price: $230

Ultralight Design

This material (similar to ROBIC nylon used by other brands for lightweight packs) is light and durable. And it passed inspection after use on some rugged Colorado trails.

It’s worth noting we only tested the pack for a week, so we will have to address durability later on. Immediately, I liked the lightweight feel of the pack, as well as the easy adjustment of the load lifter, compression, and shoulder straps.

I also like the added daisy chains on the front panel and the deep front zipper exterior pocket. There are also loops for trekking poles.

After initial testing, I will say this pack offers loads of adjustability, good weight distribution and, best of all, a comfortable fit. It definitely also fits in the ultralight and lightweight category of packs.

Things like removable hip pockets and the trash can clip-on offer some customization depending on what you like to carry, and where.

The 45L capacity was roomy enough to fit my ultralight tent, sleeping bag/pad, hydration, stove kit, first-aid kit, rain gear, layers for a couple of days, and a few personal items.

On longer, technical day hikes where I wanted to carry more gear, I was able to fit extra items like trekking poles, a water filter, and an ultralight trail chair.

While the pack is great for all the above reasons, there’s one more awesome and unique feature: back panel access.

the padded back panel zippered access on the Sun Dog 45L pack
(Photo/Mary Murphy)

The back panel gives you direct access to both the hydration bladder sleeve (for easy filling up and removal) as well as access to the lower part of the pack itself. Not having to dig around from the top opening with a full pack of layers and gear made life a lot easier.

However, the breathability definitely could be better. The padded back panel is thick (still comfortable and not stiff), but Big Agnes, I think, could’ve reduced some weight here, or used a more ventilated material.

Women’s Fit

We only had this pack in testing for a short period of time, but overall loved the fit of this pack.

Big Agnes Sun Dog 45
A view of the anatomical hip belt on the women’s Sun Dog; (photo/Sean McCoy)

The shoulder straps especially are more curved to fit comfortably around women’s chests. (The men’s pack version has contoured shoulder straps as well, but the design is different.)

The anatomical, padded (yet minimal weight) hip belt is comfortable too, with both lighter and heavier pack loads. The brand calls it an “Open Range Hipbelt,” and it’s definitely a different design than what I’ve seen in other packs.

It’s worth noting that it adjusts in two places, which can either be a plus or finicky, depending on whether you’d use this function. I definitely liked it for tailoring in the fit.

On to sizing — Big Agnes chose just one torso length on its women’s packs (Sun Dog tested here, as well as the two daypacks and the 60L Garnet) — the 16-18-inch range. While the fit of the pack is great, I do have some notes for Big Agnes on sizing.

First, the men’s packs come in multiple sizes, a medium and large, reflecting different torso ranges. It’s a bummer that yet again a women’s pack only comes in one version. (Not all women have the same torso/height!)

For example, I’m taller than average for women (5’8″) and have a torso length around 18-19 inches. My height is mostly in my legs, so I usually still find women’s/smaller packs plenty comfortable. But for anyone taller than me, that maybe wouldn’t be the case.

And to be fair, the men’s sizing is fairly limited, too. (What about a shorter male with a 17-18-inch torso?)

The men’s pack sizing ranges from 18-22 inches in torso length. It may be worth the brand adding more sizing to its pack range later to cover all heights and sizing, specifically for those who want a women’s-specific pack for comfort in the chest and hips.

Many pack brands like Osprey, Mountain Hardwear, and Gregory do this — and I hope to see it in future years from Big Agnes as they build on their pack offerings.

Pack Features

Big Agnes Sun Dog 45-9
The removable hip pockets on the Sun Dog 45L; (photo/Sean McCoy)

I touched on a lot of these pack features above, but the big ones are the trekking pole attachments, daisy chain points, mesh side pockets and outer zip pocket, removable hip pockets, and Big Agnes’ own Trash Can accessory.

Removable hip pockets — these hip pockets are nearly the perfect size. They can fit everything from a lip balm to a snack bar to a wallet and phone, and you can take them off if you are an ounce-counter.

The two side pockets offer ample space for stashing all sorts of gear: wide water bottles (we tested with a few different ones), water filters, a first-aid kit, or rain gear.

Big Agnes’ Trash Can accessory is definitely an unnecessary but fun add-on. The brand intends for it to hold camp trash and also collect litter on the trail (#LNT).

The lightweight 7L pouch is made with the same recycled, ripstop Mipan ROBIC nylon material as the pack. It easily clips to either side, and it was definitely useful for wrappers and the like.

On an overnight or thru-hike, it could act as the pouch for kitchen trash. The interior cinch cord keeps contents in, and it even comes with an attached reference card on LNT practices. However, I generally don’t like things swinging or dangling off my pack. It’s the same as the hip pockets — if you don’t want it, simply remove it.

big agnes sun dog trash can attachment for backpack
(Photo/Mary Murphy)


Overall, the Sun Dog pack performed well in lightweight missions in the mountains. Its ROBIC nylon material stood up to light rain and wear. I didn’t have any immediate cons, other than the breathability of the back panel and feedback on the sizing.

This pack is definitely a contender in the ultralight space with ones from Arct’eryx, Granite Gear, and Hyperlight Mountain Gear. Compared to a Hyperlight Mountain Gear 2400, the Sun Dog offers slightly more volume and is nearly $100 cheaper.

The Sun Dog 45L pack is available now at Big Agnes and will be soon at REI. The men’s similar version to the Sun Dog is the Prospector 50L and is also available now.

Check Availability at Big AgnesCheck Availability at REI

the author wearing the Big Agnes Sun Dog 45L ultralight pack
(Photo/Sean McCoy)
big agnes tiger wall UL solution dyed yellow tent in the sun
Ultralight Tent With an Ultralight Footprint: Big Agnes Solution-Dyed Tiger Wall UL2 Review
Ultralight and sustainable? Big Agnes has nailed the next iteration of must-have camp gear with its solution-dyed Tiger Wall UL tent. Read more…

Leave a Comment