Best Ultralight Sleeping Bag

Sharing is caring!

This is a review of the Best Ultralight Sleeping Bags for backpacking in 2023.

There are so many choices of backpacking sleeping bags on the market. I’ve researched, tested, and used sleeping bags for thousands of nights. And I’ve narrowed the field down to only the Best Lightweight Sleeping Bags.

All the sleeping bags were chosen for their quality, lightweight, and small pack size. All the backpacking sleeping bags in this review will last you many years and make a good investment.

If you are looking for an even lighter option then take a look at the Best Ultralight Backpacking Quilts.

---

Best Lightweight Sleeping Bags for Backpacking 2023

The Best Lightweight Sleeping Bags for Backpacking in 2023 are:

• Zpacks Mummy Sleeping Bag
• Sea to Summit Spark 3 18F
• Rab Mythic Ultra 360
• Therm-a-Rest Hyperion 20F
• Zpacks 20F Hoodless Classic Sleeping Bag
• Zpacks Zip Around Sleeping Bag
• Feathered Friends Hummingbird
• Macpac Dragonfly 400
• REI Magma 15F
• Western Mountaineering Ultralite
• Marmot Phase 20F

The Zpacks Mummy Sleeping Bag is not only a lightweight sleeping bag but it has a full length zip that can turn it into a quilt. This makes this sleeping bag one of the most versatile sleeping bags on the market at the moment.

The Zpacks Mummy Sleeping Bag comes in 2 widths, 3 lengths, and in 4 colors, namely green, blue, black, and my personal favorite orange. I tested the standard width and found it to be a perfect width that allowed me to move around inside the sleeping bag without feeling cramped. If you are a large build or like plenty of room inside your bag then you could opt for the wide version.

Unlike most ultralight sleeping bags on the market, it features a full length zip that can be unzipped and turned into a backpacking quilt.

It is overstuffed with 30% extra 900 loft water-resistant down. I love this feature. It allows you to use the bag more before it needs to be washed. Perfect for the long-distance thru-hiker.

No doubt the full length zip makes the bag heavier than it could be with a quarter length zip, but the ability to use the bag in a more varied range of temperatures and situations is a good compromise.

It comes with an oversized Dyneema stuff sack. Not only is the stuff sack waterproof but the large size makes it easy to pack up the bag in the morning and can be compressed further if needed.

Overall, the brand new Zpacks Mummy Sleeping Bag is the best full zip mummy sleeping bag for 2023. The versatility of this mummy bag allows it to be used as a backpacking quilt and is sure to be very popular on thru-hiking trails around the world in 2023 and beyond.

The Sea to Summit Spark 3 was updated in 2019 with a change to vertical baffles in the torso region to prevent down shift when moving around in the bag. And in 2022 they upgraded the DWR coating to a PFC free DWR on the freaky lightweight and almost transparent 10 Denier outer shell.

With these upgrades, combined with a light weight of only 23.5 oz / 665 g this bag is super lightweight and very high quality. With 15.2 oz / 430 g of Hyperdry 850+ loft down fill it has some of the highest amounts of down fill in this Sleeping Bag review. Which makes for a great warmth-to-weight ratio. And if you want more warmth they even have the Spark 5F / -15C.

Another bonus is the sleeping bag has been independently tested to the EN / ISO standards. The Sea to Summit Spark III is EN rated at a limit rating of 18F / -8C and a comfort rating of 29F / -2C.

The Sea to Summit Spark III / 18F is also one of the roomiest ultralight bags in this review and has a full-length zip, which adds a little to the overall weight of the bag in comparison to others in this review. That small amount of extra weight allows you to open the bag into a quilt when the nights are warmer.

Overall, the Sea to Summit Spark has a very small pack size and top quality everything. With all the upgrades over the years, the Spark is one of the best lightweight sleeping bags for 2023. And it comes in different temperature ratings so if you want something slightly warmer or something a little less warm, they have you covered. Did I mention, that it is reasonably priced in comparison to the other best backpacking sleeping bags in this review.

At 21.4 oz / 606 g the Rab Mythic Ultra 360 was released in 2022, replacing the very good Rab Mythic. The Rab Mythic Ultra is even lighter than the older Mythic 400 which I loved as an ultra-light sleeping bag. Like the Marmot Phase 20 and the Sea to Summit Spark, this bag is EN / ISO rated so rest assured that it will definitely keep you warm when the temperatures get cold.

The Rab Mythic 360 is EN rated at a limit rating of 20F / -7C and a comfort rating of 28F / -2C. It is stuffed with high-quality 900+ down for great warmth to weight ratio. It also uses a brand new fabric that increases the insulation ability of the sleeping bag by trapping heat the same way an emergency space blanket will trap heat.

The half zipper length cannot be completely unzipped. This option makes it unsuitable for warm summer nights but does a perfect job of weight saving.

This would be one of the best sleeping bags for thru-hiking a trail such as the Continental Divide Trail. It would also be perfectly suited for lower altitudes in the Himalayas and Andes or any non-summer hiking where temperatures regularly hover near or below freezing.

The Therm-a-Rest Hyperion 20F is the lightest and most compact sleeping bag in this review. Weighing in at only 19 oz / 550 grams and with a pack size just a little bigger than a water bottle it is an impressive ultralight sleeping bag.

The Therm-a-Rest Hyperion 20F is EN rated at a limit rating of 20F / -6C and a comfort rating of 32F / 0C. I found these temperature rating to be spot on when I tested the bag. It is made from thin 10 Denier inner and outer fabric. And uses hydrophobic 900 fill down that is responsibly sourced.

A large amount of weight savings comes from the narrow internal dimensions of the bag. It is one of the tightest fitting bags in this review. If you are primarily a back sleeper it will suit you perfectly, but if you are a side sleeper or like to toss and turn during the night it does not offer much internal room.

To reduce weight to the absolute minimum the sleeping bag packs 70% of the down on the top and sides of the bag with only 30% on the bottom. So rolling over during the night will not be as thermally efficient as being a back sleeper. It also has a clip and strap to go under your sleeping pad to keep the bag in place.

Overall, the Therm-a-Rest Hyperion 20F is the best ultralight backpacking sleeping bag for back sleepers. If you are not a back sleeper then this may not be the best choice for you.

Zpacks is well known for only producing ultralight gear and the Zpacks 20F Hoodless Sleeping Bag keeps with the ultralight ethos of the company. The bag features ultralight 7D fabric on both the inner and outer shell. It is also coated with a DWR inside and out in case you find yourself in damp conditions. It also has a 3/4 zipper length so it can be opened and used as a quilt in the warmer summer months.

The Zpacks 20F Hoodless Sleeping Bag is filled with water-resistant Downtek 900+ Goose Down which is treated to be resistant to water. As a result, the bag has a great warmth-to-weight ratio.

The bag comes with many size options and a good choice of colors that few other companies can match. If you are slightly larger or smaller than your average hiker then you will appreciate the size choices. I like the color options too.

The bag comes without a hood so you will need a down hood or fleece balaclava or similar to keep your head warm when it gets cold. And the hoodless sleeping bag is not ISO rated. The temperature rating has been self-assessed.

Overall, the Zpacks sleeping bag is the best hoodless sleeping bag for ultralight thru-hikers and backpackers who want the best and lightest bag on the market in 2023.

Part Sleeping Bag, part Quilt. That is how you could describe the brand-new Zpacks Zip Around Sleeping Bag. Like the Classic Sleeping Bag mentioned above, it is a hoodless sleeping bag. It is not only an ultra-lightweight sleeping bag, but it features a full-length zipper that increases the versatility of the bag by allowing you to fully unzip the bag, thus turning it into a quilt. Perfect if you find yourself on a backpacking trip that includes both hot weather and cold.

I tested the Zpacks Full Zip Sleeping Bag in warm weather. It was great to be able to fully unzip the bag and use it as a backpacking quilt.

The full-length zipper increases the weight of the bag slightly compared to other Zpacks sleeping bag models, but that increase in weight also increases the versatility of the bag. And if you ever thought of buying a backpacking quilt but never dared to try, then this is for you.

The zip and neck area has a draft tube to keep the heat in when needed and the zip has a strip of webbing to prevent snagging. When I tested the bag I found the anti-snag zip worked well and as promised.

The Zpacks Zip Around Sleeping Bag comes in a Dyneema stuff sack that is waterproof and slightly oversized to make packing easy. Want to compress the stuff sack? Easy, just sit on it after you packed it up.

It comes in 4 color choices, 2 width choices, and is available in a 10F, 20F, and 30F temperature range.

Overall, the Zpacks Zip Around Sleeping Bag is the best full zip sleeping bag for 2023 and one of the most versatile sleeping bags or sleeping quilts you can buy.

The Feathered Friends Hummingbird is one of the lightest down bags rated at 20F (-7C). It weighs 24oz (680g) and is stuffed with the highest quality 950+ down which helps save weight and gives you the best warmth-to-weight ratio of any of the bags in the review.

This is a mummy bag that is suited to someone who wants the lightest bag possible and is not prepared to compromise on quality. The Hummingbird is roomy enough for most people but Feathered Friends has larger models for those wanting more internal room.

Triple Crown Hiker Rob “Stone” Sweeney has used the Feathered Friends Hummingbird on the Continental Divide Trail, Arizona Trail, Hayduke Trail, Finger Lakes Trail, Long Trail, Colorado Trail, John Muir Trail, and The Grand Enchantment Trail. He likes the lightweight, small pack size, high build quality, and has had no issues with the zippers or cords.

Despite washing the bag at the end of every hiking season it is starting to develop some clumping issues. After an amazing 5000+ miles / 8000km of use, it is starting to develop cold spots. The down is getting pushed to the sides when he turns in it, leading to cold spots overnight. Follow his journey on Instagram: @HikingStone

If you want more room inside the bag, look at the wider Swallow or Swift down bags, or even take a look at the Feathered Friends Flicker which is a hybrid sleeping bag and quilt. They have the same high-quality materials with slightly larger internal dimensions and weight.

Although this back is not EN Rated it has similar specs to the Marmot Lithium 20 and RAB Mythic Ultra 380 which are both EN Rated. A great high-quality lightweight sleeping bag.

The Macpac Dragonfly 400 is a brand new, fully updated sleeping bag from Macpac. The mummy sleeping bag has 14.1 oz / 400 grams of 800 loft Hyperdry down stuffed inside a 15D Pertex outer fabric with a DWR finish. It also uses a 1/3 length zip to help reduce the weight of this lightweight sleeping bag built for the moist conditions of New Zealand.

I tested this bag and found it had generous internal dimensions that worked well when side sleeping, sleeping on my back, or sleeping on my stomach. It also had a good hood which combined to keep me warm inside the bag. In fact, the hood on the Macpac Dragonfly is the best in class and the best hood out of all the sleeping bags in this review. I also tested the outer fabric for water resistance and it was able to keep water from entering the bag. Any water that may have got into the bag made little difference to the HyperDry down which kept its loft.

The sleeping bag comes with a very good compression sack which is able to compress the sleeping bag into a very small size. When not using the bag there is also a larger lofting bag to keep the down well lofted when not on the trails.

Overall, if you are living in Australia or New Zealand and looking for a lightweight sleeping bag for bushwalking or tramping then this is one of the best.

The REI Co-Op Magma 15F is a good lightweight sleeping bag for backpacking at a reasonable price.

The REI Co-Op Magma 15 uses a good quality 15D Pertex shell with high-quality 850+ loft goose down that has been treated to resist water. Add to that the small pack size and good warmth-to-weight ratio and this makes a good backpacking sleeping bag for someone wanting good quality but not top dollar.

This is the heaviest backpacking sleeping bag in this review. This helps justify the slightly lower price in comparison to higher-priced bags. It will be well suited to someone on 3 season backpacking trips wanting a good quality sleeping bag.

Overall, the REI Magma is the best budget sleeping bag that still is lightweight, has a small pack size, and good warmth-to-weight ratio.

Western Mountaineering makes some of the best quality bags but that comes at a high cost. The 29 oz / 820 grams sleeping bag is one of the most expensive bags in this review. The reward for spending this much money is a sleeping bag that will last a very long time.

The Western Mountaineering Ultralite is a mummy bag with enough room for all but the widest of people. It uses 850+ down unlike some of the other manufacturers that use the highest rated 950+ down. The bag is rated to 20F (-7C) and Western Mountaineering has a large selection of bags rated at different temperatures.

Overall, the Western Mountaineering Ultralite is one of the best quality sleeping bags money can buy right now and one of the best lightweight sleeping bags for backpacking.

At 23oz / 660g the Marmot Phase 20 sleeping bag is one of the lightest of all the sleeping bags reviewed and one of the best budget ultralight sleeping bags.

The Marmot Phase 20 Sleeping Bag is EN tested 20F / -7C rated sleeping bag, so rest assured it will keep you warm.

The mummy style of most ultra-lightweight bags can be constrictive for some people. It is a mummy bag with similar internal specs to the Feathered Friends, Western Mountaineering, and RAB sleeping bags.

This bag comes in at a bit cheaper than the other ultralight bags without compromising quality or materials. Be aware that there are not many of these bags available as they have been discontinued. So for those wanting the best quality at a reasonable price, this is the best option, if there are any left!

---

Other Sleeping Bags Yet to be tested

• Nemo Disco: The Nemo Disco is one of the roomiest sleeping bags and is great for side sleepers.
• Feathered Friends Tanger 20 Hoodless: The Feathered Friends Tanger 20 Hoodless is another hoodless sleeping bag that is light on weight, and compact.

---

Buyers Guide

Here is all the information you will need to make an informed decision about Quality down Sleeping Bags. Recent years have seen the weight and pack size of bags reduce and the quality rise. For anyone who still has a bulky, heavy, or poor-quality bag it is time to consider throwing down some money on an upgrade.

---

Weight

All the Lightweight Sleeping Bags in this list weigh less than 2 lb / 900 grams with many quite a bit lighter than that. For anyone heading out on a backpacking trip in temperatures around freezing or just below will find the bags on the list to be sufficient. Gone are the days of needing to take a heavy and bulky sleeping bag.

Every year companies are producing lighter sleeping bags with the shell material getting lighter and stronger, and the down fill power getting higher and higher. Suffice to say, sleeping bags have improved a lot in recent years with regard to their weight to warmth.

---

Fill Power

When you see a sleeping bag filled with 900 loft down, it is referring to the fill power. The number is a specific measurement of the down quality. It is measured by placing 1 ounce of down in a container and placing a small weight on top to compress the down just a little. How much the down expands within the container is measured in cubic inches. Therefore 1 ounce of 900 loft down will expand to 900 cubic inches.

---

Hydrophobic Down

If down gets wet it will absorb the water and clump. If this happens on a cold night it can be fatal. As a result, hydrophobic down was invented.

Many but not all of the sleeping bags in this review use some form of hydrophobic down. Most use some form of proprietary name for their down treatment but they are effectively the same.

The water-repellent down will not absorb as much water as normal down. This is a reassuring factor that adds to your safety when heading into the backcountry.

---

Sustainable Down

Most sleeping bags use Responsible Down Standard (RDS) which is a worldwide certification program for down material. It prescribes that the down used in your bag has been responsibly and ethically sourced. And the harm to the animal has been kept to a minimum. But you should know that the down in your bag has come from either a duck or goose and is a by-product of the meat industry. Some companies provide certification with the sleeping bag which will tell you all about where the down was sourced, what fill power it is, and more.

---

Shell Material

All the sleeping bags in this review use an outer shell material of between 15 denier and 7 denier. 15 Denier is more durable and stronger than 7 Denier. This light fabric is just one of the reasons why bags are so light. This compromise in material strength can mean that bags can rip and tear if you are not careful.

I’ve spent thousands of nights in a sleeping bag in a tent, sleeping on the ground, in hammocks, and everywhere in between. I’ve only put a couple of holes in bags, usually my fault (don’t air out your sleeping bag near a barbed wire fence!). A small amount of duct tape or tenacious tape is sufficient to repair the bag.

---

DWR Coating

Most sleeping bags are prone to be exposed to bad weather so manufacturers add a DWR coating to the outside of the shell. this chemical coating will cause water to bead as it does on a car after you wax it. As it beads it runs off the outer surface. Just another thing added to keep you warm at night.

I extensively tested the DWR Coating on many of the Sleeping Bags in this review and found the DWR Coating, in combination with a good quality shell fabric and water resistant down, all combine for prefect all-weather performance.

---

Baffles

Baffles are the sections of the sleeping bag that have the down stuffed inside them. They are usually either vertical baffles or horizontal baffles. These styles of baffles do a good job of locking in as much heat as possible.

The vertical baffles are usually used in the torso area and do a great job of preventing any down from shifting during the night. If you are a side sleeper that means this design prevents the down from moving around too much during the night.

The horizontal baffles are usually at your feet to maximize the warmth of your feet. If you suffer from cold feet then you will like this design.

---

Down vs Synthetic Sleeping Bags

This review is only dealing with the best Lightweight Down Sleeping Bags that are filled with down. It would be unfair not to mention the other option which is the synthetic sleeping bag.

They are heavier and don’t pack in the same compact size as down bags. But they still insulate when wet and are cheaper, therefore many people see their value. A wet sleeping bag that uses down will not keep you warm, but if it uses synthetic you will still stay warm, even if it is not very comfortable.

As materials continue to develop there may come a time when synthetic bags are better than down. That point has not been reached yet.

That being said, if you want to save money or are heading to areas where getting your sleeping bag wet would be life-threatening, consider a synthetic bag. Overall, when you want the best warmth-to-weight, most bags will be using down fill.

---

Warmth and Temperature Rating

A word of warning about temperature ratings. Not all bags are rated the same. Some are self-assessed and some use EN / ISO independent standards. Keep in mind that the bags in this review that are rated at 20F will not necessarily give a good night’s sleep at that temperature. They usually keep you warm and give you a good night’s sleep at temperatures around or just below freezing.

Most of these sleeping bag manufacturers have self-determined the temperature ratings of their bags. As a result, they are not always the best guide of what is a comfortable rating. The industry used to recognize EN 13573 rating standard but it has recently been replaced by the improved ISO 23537 standard.

It can be expensive for companies to obtain this rating, few lightweight Sleeping Bag companies seem to bother. I’ve used EN-rated bags in the past and find them to be a very accurate measure of temperature rating. The fill weight or amount of down fill inside the sleeping bag or quilt varies quite a bit between all the manufacturers.

This might not seem like much but it can make a difference to the insulation of the bag. It would be easy to claim that the width or style of the internal baffling could lead one manufacturer to have a competitive advantage over another, and that may be the case.

The way internal baffles are constructed also affects the temperature rating. In some bags, the down can be moved within the internal baffles to where it is needed most. I find this feature very annoying.

I want to unzip my sleeping bag to regulate the temperature, not wake up in the middle of the night and try to shuffle down within the baffles.

The Mummy Bags in the review are all rated at around 20F (-7C) which is a good functional 3-season temperature range that can be used in all but the coldest and warmest of weather. Down mummy bags also offer the best warmth to weight.

Also, keep in mind the temperature rating and quality of your Ultralight Sleeping Pad. A sleeping pad with little or no insulation will allow the cold to suck through the sleeping bag making you very cold. So make sure you have a good sleeping pad.

If you need to be a little warmer you could use an insulated sleeping bag liner to increase the warmth of the sleeping bag. If a sleeping bag liner is not enough you may need to take a look at upgrading to a 4 season winter sleeping bag.

---

Stuff Sacks

Keeping a sleeping bag dry while hiking is critically important. Heavy rain, a leaking backpack, or a fall when crossing a river can make for an uncomfortable night’s sleep at best and a life-threatening situation at worst.

For many years I have used a Thermarest fleece stuff sac. Since then I’ve taken a look at the Best Backpacking Pillows and prefer to use a Sea to Summit dry bag for my sleeping bag stuff sack.

Recent years have seen many ultralight hikers make the switch to Dyneema stuff sacks such as those from Hyperlite Mountain Gear and Zpacks. These super lightweight, strong, and waterproof stuff sacks come in multiple sizes and shapes to fit any sleeping bag and are a good investment to keep your down bag dry.

---

Women’s Sleeping Bags

All the sleeping bags in this review are unisex but there are also women’s specific sleeping bags. They generally are a little smaller in length and have more down fill around the chest area and feet. In general, women don’t sleep as warm as men and require a warmer-rated sleeping bag.

---

Price

Most Ultra Light Sleeping Bags can cost a lot of money but it is money well spent. It is not unusual to keep a quality sleeping bag for 10 years. I kept a quality winter sleeping bag for 20 years before I decided to sell it.

In most cases, it is not only money well spent, but one of the best investments you can make. All of the bags listed will last 10 years or more and range in price from US$280-$680.

---

Warranty and Return Policy

Before purchasing a Sleeping Bag be sure to check the return policy. Make sure you can return it if you ordered the wrong size.

If it is returned after being used it may incur a ‘Cleaning Fee’.

Anything purchased from REI offers the best consumer protection, closely followed by Amazon with a 30 day return policy. In all cases, buyer beware, make your choice wisely.

---

How to wash a Sleeping Bag

Once you have purchased an Ultralight Sleeping Bag listed above it is time to look after it.

There are several ways to wash a down bag. The best methods are to hand wash them in a bathtub or on a gentle wash cycle in a front-loading washing machine. It is my preference to wash my bag in a front-loading washing machine.

The first step is to purchase a detergent that is specific for washing down, such as Nikwax or Grangers. Be sure to read my full information guide on how to wash down sleeping bags.

---

Storage

When you are not using your bag it is a good idea to store it lofted in a lofting bag. Although sleeping bags can be stored in their compression stuff sack indefinitely they will loft up quicker when not compressed for a long period of time.

It is very important that they be dried prior to storing. And it goes without saying that they should be stored in a dry place away from critters that may chew through your investment.

---

Sleep System

A Backpacking Sleeping Bag is only part of a good backpacking sleep system.

You need a quality Sleeping Pad that has an appropriate warmth rating to reduce the transfer of cold from the ground to your body.

A Backpacking Pillow used to be a luxury item but things have changed in the last couple of years. They are now lightweight and comfortable. There is no longer any excuse not to take one with you.

If you need to increase the warmth of your bag you could get a sleeping bag liner. If that doesn’t provide enough warmth for the areas you are going then consider upgrading to a winter sleeping bag.

---

Conclusion

Which is the best ultralight Sleeping Bag for thru-hiking and Backpacking? Any of the backpacking sleeping bags listed in this review would make a great option for anyone wanting to lighten up the weight they carry.

The following Ultralight Backpacking Sleeping Bags are highly recommended:

• Zpacks Mummy Sleeping Bag
• Rab Mythic Ultra 360
• Sea to Summit Spark 3 18F
• Therm-a-Rest Hyperion 20F
• Zpacks 20F Hoodless Classic Sleeping Bag
• Zpacks Zip Around Sleeping Bag
• Feathered Friends Hummingbird
• Macpac Dragonfly 400
• REI Magma 15F
• Western Mountaineering Ultralite
• Marmot Phase 20F

Most of the Sleeping Bags are almost identical in quality, weight, and pack size. They are all a great choice and I would be happy to buy any of them. The only thing separating them is the price and the buyer’s location.

Overall, I would choose the Zpacks Mummy Sleeping Bag by a small margin from the Sea to Summit Spark and  Rab Mystic Ultra 360, due in part to the lightweight and full zip that adds a degree of versatility that no other bag can match, making it the best sleeping bag 2023.

For those living in Europe, RAB might be the cheapest and most available.

For those in Australia and New Zealand, you should buy through Snowys.com or Macpac. With either the Macpac Dragonfly or Sea to Summit Spark being the best options.

The ultralight sleeping bags should always be used in conjunction with a high-quality, lightweight sleeping mat and backpacking pillow.

---

Frequently Asked Questions

---

Sharing is caring!