If you love sleeping outside but hate mummy bags this is the bag you have been waiting for. For all of us side sleepers out there this has been a long time coming and we should all start getting excited!

Just The Facts:


Specifically designed for people who sleep on their sides with a technical fit, patterned to move with you as you roll from one side to the other

Close fitting, jacket-style hood keeps insulation close to the body without sacrificing mobility

Keep pillow in place with unique Pillow Barn made of stretch mesh material with interior access from either side for easy adjustment

Optimized warmth and minimized pressure points with body mapped insulation

Improved shell fabric and lining with PFC-free water repellent finish

Down fill with a PFC-free water repellent finish throughout the bag provides lofty warmth while synthetic insulation helps alleviate common pressure points in the hips and feet

Optimized fit and thermally efficient footbox is patterned to mimic the shape of your foot position while lying on your side

Smooth, quick zip with anti-snag locking zipper with no-draft zipper garage, and long, ambidextrous zipper

Easily adjust hood without unzipping using low-profile internal cordlock access

Seal out drafts by cinching insulated tube along upper hood opening

Hang dry or store bags with exterior loops

Storage sack & stuff sack included

Specs + Sizing

Bag WeightRegular: 2lb 4oz / 1.02kg / Long: 2lb 8oz / 1.13kg
Fill WeightRegular: 19oz / 538g / Long: 21oz / 604g
Compressed Bag SizeRegular: 6.5″ x 8″ / 16 x 20cm / Long: 7.5″ x 8″ / 19 x 20cm
Stuff Sack SizeRegular: 8″ x 17.5″ / 20 x 45cm / Long: 8″ x 17.5″ / 20 x 45cm

My Story:

When I was first sent the Big Agnes Sidewinder I was so freaking excited I could hardly contain myself. It was cold and nasty out but I was dreaming of spring/summer backpacking trips. As a side sleeper this was going to be a huge win for Big Agnes and myself if it worked out. So, I waited….. and waited….. and waited. The winter never seemed to end

I came home from Maui and decided I could wait no more and a packed my truck to head up for what I hoped would be my first trip of the season. Who knew we would get a freak snow storm that night?

It was at this moment I knew I messed up!

After so many failed attempts to get un stuck I decided that I would have to spend the night in the truck and hike out to cell service the next day.

side sleeping at its finest!

That was not the adventure that I was hoping for. So, I had to get the plans rolling for the next chance to get out into the wilds. It took an entire month before the hills were clear enough to get back up. I had to camp much lower than I wanted to but it did the trick.

All set up.

It got down to about 38 on my first night and I was very comfortable. The bag was freaking phenomenal! I have never been so comfortable in a mummy bag as I was on that night. Side, back, or stomach it didn’t matter. I was so impressed!

Snug as a bug in a rug!

I was gearing up for a very active season when disaster hit. That Covid monster hit my household hard. Long story but it took me out of the game for several months. When I was finally able to get back out on the trail I was so pumped to try my last testing area for this bag. I love to hammock camp and while you might think that is not a great test for a side sleeper, I assure you it is. I always start on my back but end up on my side. In a hammock where things are already tight a traditional mummy bag is just not the ticket. I typically use quilts as they are the compromise. Well, the Sidewinder might very well have changed the game forever.

Getting set up.

Overall, my very long testing period of this bag has been fantastic. I really love it and it will become my go-to mummy bag for the future. I love the sub 3lb weight, the integrated pillow sleeve, the side sleep design, the packability BA is known for, the price point of $299, and the color is pretty dang cool. This bag checks all the boxes for a 3-season bag and it is one that I’m confident you will be happy with.

What can be done better?

The only thing that I was a bit unhappy with was the feathers/down coming out of the fabric. This is bound to happen with all down bags but I felt it was a bit more prevalent with this bag than others I have tested. Not sure what the cause of this is but I feel sadness with every feather that escapes the bag. It’s like watching a little comfort buddy fly away.

Big Agnes Sidwinder $299
  • Functionality
  • Value
  • Ergonomics
  • Durability


If you love sleeping outside but hate the constriction of mummy bags, this is the bag you have been waiting for. For all of us side sleepers out there this has been a long time coming and we should all start getting excited!


Sub 3lbs

$299- Great price for a quality down sleeping bag

Designed for side sleepers.

Variety of temperature ratings to fit your needs


Loss of down through the fabric. Not excessive but noticeable. 

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