Australian Hiker

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Sea to Summit Spark Pro -9℃ Sleeping Bag Regular Review

For a number of years I used one of the older Sea to Summit Spark models which are all but impossible to find these days. This older bag was designed with ultralight hikers in mind being very lightweight and compact and with that, containing minimal features. In preparing this review of the new Sea to Summit Spark Pro -9℃ Sleeping Bag I read through that older review and looked at what I perceived as shortcomings with that bag. I was pleasantly surprised to see that Sea to Summit had pretty much covered off everything and probably a few other things I hadn’t identified.

First up Sea to Summit has rationalised its range of sleeping bags and instead of the male and female versions having different names they have now created a larger Spark family range. While they actively sell a female specific Spark bag, nowhere does the Spark Pro get identified as a men’s bag although you only have to look at the advertising material given women are no where to be seen!

Realistically the Spark Pro Sleeping Bag comes in a range of two options that includes a -1℃ version and -9℃ (this bag) both sitting in the technical range. Whereas its predecessor has minimal features and really was only suited to the temperature at which it was rated, this new range is highly versatile.

First up this bag has the ability to zip in all sorts of directions and can be zipped to the Sea to Summit Spark Women’s Sleeping Bag. God knows why because as much as I love my wife sharing a sleeping bag isn’t high on the list of my priorities!

In addition, the Spark Pro can be fully zipped open to create a flat quilt which was something the older model could never do. What this means is that this new version is highly versatile and can be used in warmer weather though I would still want a lighter weight bag when the summertime temperatures hit. The draught tubes on this sleeping bag are very cushy and if you really want to keep yourself warm and zip the bag up entirely, the draught tubes will help in restricting air movement. Alternatively you can unzip the side or bottom zip or the entire bag to get the perfect comfort level.

The Spark Pro range uses 950+ down for its warmth and what this means is that the regular bag which is designed to fit 180cm tall men, fits me well but  doesn’t come with a big weight impost or is bulky in your pack. In fact this bag weighs 784 grams which is very impressive for a bag of this warmth with all these features. In addition to using the top grade of down, it’s treated to keep you warm even if the bag becomes damp (note they don’t say ‘wet’).

This bag is rated as a three-season bag but if paired with a high grade sleeping pad such as the Therm-a-rest NeoAir XTherm NXT Sleeping Pad would definitely get you through all but the coldest winters. Most sleeping bag manufacturers these days work on the magic number of 20℉ (-7℃) to meet the needs of the US long distance trails so it is no accident that this bag is designed for -9℃ to cater for that market. If you are a female using this bag then the comfort rating is -3℃. In Australia you would be hard pressed to be hiking in conditions that cold so this is a year round bag. Sea to Summit has retained the two directional baffles with the top half of the bag having vertical baffles and the bottom half having horizontal baffles. This directional series of baffles helps to keep the down where its needed to maintain the appropriate level of warmth.

The colour of this bag is a combination of black and dark olive compared to the older models which were light grey and yellow. This means the newer bags are less likely to show dirt which is a big bonus. In terms of fit, at the time of this review I weigh just over 110 kg, am fairly large chested, and have size 15 US feet and even though this is a mummy bag, I didn’t feel cramps. If I was any taller I would have opted for the long size of this bag which will suit hikers up to 198 cm in height.

As with all Sea to Summit bags they come with a large storage bag for long term storage at home as a well as a compassion sack for use on the trail.

The only real negative from my perspective is that the shell material on this bag is deliberately on the lighter side. So long as you handle this bag gently it will last of years and years as my older model has but I wouldn’t be inclined to lend this bag to a non-hiker or use it as a hire bag.

Price wise this sleeping bag isn’t cheap coming in at just under AUD $999.99 RRP but for a bag of this quality it packs an awful lot of features that are hard to beat. Sea to Summit continues to improve its sleeping bags with each update and without a doubt this is the best version of a ‘technical bag’. While this one could have been lighter by stripping out features it is an extremely warm and versatile bag that will suit hikers in all but the hottest conditions making it easy to justify the purchase price.

If you are hiking year round in conditions that get cold and want to carry a toasty warm sleeping bag that doesn’t fill up half your pack, then this is the one to choose!

We Like

• Extremely versatile opening in a number of ways including to a flat quilt
• Compressed volume: 7L
• Lower Temperature Rating is -9℃ so its suitable for 3-4 season use
• 950+ Fill Power Goose Down
  • High loft and excellent warmth-to-weight ratio
• Non-PFC Ultra-Dry Down Treatment which maintains loft and warmth even in damp conditions
• Excellent hood with cushy neck and head draught collars
• Anatomical foot box that provides extra space and comfort for even those with bigger feet including my size 15 US feet
• Ergonomic Mummy Shape ensures a snug fit for maximum warmth
• Full Box Baffles that prevent down migration for consistent insulation
• Ultra-Sil Compression Bag and Storage Cell which facilitates compact packing and easy storage
• Dark colours inside and out so it doesn’t show the dirt like the older model
• Can be joined with the Female Sea to Summit versions for a double bag

We Don't Like

• On the upper end of the price range but great value for money
• Handle with care as the outer and inner shell are lightweight and potentially fragile if you are too rough

Best Uses

• The perfect bag for ultralight hikers who want maximum warmth, minimum weight and that right size in their sleeping bag

Buy One

You can purchase the Sea to Summit Spark Pro -9℃ Sleeping Bag Regular from Snowys, or from Wildfire Sports

Disclosure:  We may earn a small commission, at no additional expense to you, if you click through and make a purchase. Please note that our affiliations do not influence, in any way, the independence of our reviews. If we don’t like a product, you’ll hear about it from us!

Investment

AUD $999.99 RRP. Often on sale at a sharper price

Other Versions

The Spark Sleeping Bag range includes men’s and women’s options as well as the Spark Pro in different temperatures ratings

Sea to Summit Spark Pro -9℃ Sleeping Bag Regular

Sea to Summit Spark Pro -9℃ Sleeping Bag Regular temperature ratings. This bag will suit the ‘average female’ down to -3°C and the ‘average male’ down to -9°C

Sea to Summit Spark Pro compression sack. Fully compressed it will take up 7 litres of same in your pack

Sea to Summit Spark Pro in its storage sack

Sea to Summit Spark Pro draught tube on the top of the bag greatly helps to minimise air flow and keep you warm

Quilt Lock on the Spark Pro will mate with Sea to Summit quilts to create a sleeping bag layering system

Disclaimer

This review was done with product provided by Sea to Summit for testing

Last updated

25 November 2025

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