Sleeping bag comparison: Sea to Summit Spark vs Spark Pro
Choosing the right sleeping bag can make or break a night in the backcountry, and we get asked about this pairing more than almost any other in our range. Both the Sea to Summit Spark and Spark Pro are built for hikers who count every gram, but they're not the same bag wearing two different price tags. Below, we break down the differences so you can work out which one deserves a spot in your pack.
Why the right sleeping bag changes everything
Image: Sea to Summit Spark Sleeping Bag
A great sleeping bag isn't just about warmth, it's about waking up ready for another big day on the trail. Get it wrong and you're either lugging around unnecessary weight or shivering through the night. We've put together our guide on what to look for in a sleeping bag before you buy, which is worth a read before you commit to either of these options.
Sleeping bags: what sets the Spark and Spark Pro apart
The Sea to Summit Spark uses RDS-certified 850+ fillpower goose down, while the Spark Pro steps up to 900+ fillpower for a better warmth-to-weight ratio. The Spark is offered across four temperature ratings, from a summer-friendly 7°C down to an expedition-ready -18°C, and even comes in a double option for couples.
Image: Sea to Summit Spark Pro Down Sleeping Bag
The Spark Pro is more specialised, available only in -1°C and -9°C ratings, but it adds a Free-Flow Zip system that lets you fully vent the bag or open it flat like a quilt on warmer nights. We've covered this bag in more detail in our full review of the Sea to Summit Spark down sleeping bag.
Watch our video Comparing Spark & Ascent Sleeping Bags
If neither of these feels right for your trip, our team also loves the Ascent for hikers who want a touch more room and warmth. Read why hikers swear by the Sea to Summit Ascent sleeping bag for the full story or watch the video above.
Benefits and Features of the Sea to Summit Spark vs Sea to Summit Spark Pro
| Feature | Sea to Summit Spark | Sea to Summit Spark Pro |
|---|---|---|
| Down fill power | 850+ fillpower RDS-certified goose down | 900+ fillpower RDS-certified goose down |
| Temperature ratings | 7°C, -1°C, -9°C, -18°C | -1°C, -9°C |
| Minimum weight (Regular) | 363g (7°C model) | 619g (-1°C model) |
| Zip system | YKK #5 zipper with zipper plow | Free-Flow Zip System, opens flat as a quilt |
| Standout benefit | Widest range of ratings and a double option | Maximum warmth for minimum weight, plus quilt-mode versatility |
| Starting price* *As at 31 July 2026 |
$499.90 AUD | $849.90 AUD |
Don't forget your sleeping mat
Neither sleeping bag performs at its rated temperature without a decent sleeping mat underneath you. Sea to Summit tests these bags assuming a mat with an R-value of 5 or higher, so pairing your new bag with the wrong mat can leave you colder than expected. A quality sleeping mat for camping also adds comfort, insulates you from the cold ground, and protects the down from getting compressed and losing loft. Have a browse of our range of inflatable sleeping mats to find the right match for whichever Spark you choose. Check out the example below with the Ether Light XR Sleeping Mat
Image: Sea to Summit Ether Light Insulated Sleeping Mat
Which sleeping bag should you choose?
If you're chasing the lightest possible setup for alpine or search-and-rescue conditions, or you simply want the flexibility of a quilt on milder nights, the Spark Pro is worth the extra investment. If you want more flexibility across seasons, or you're camping as a couple, the standard Spark and its wider range of ratings will likely serve you better.
Why shop your next sleeping bag with us
We're a family-owned Australian hiking, camping and travel business, and we've built our reputation on genuinely knowing this gear inside out. With over 2,000 five-star reviews from our community, including hikers, alpine climbers and search-and-rescue crews who've trusted our advice in serious conditions, we back every sleeping bag we sell with expert guidance and after-sales support you can rely on.
Image: Our Operations Manager Kris uses the Sea to Summit Spark Pro.
Why Shop Sleeping Bags & Sleeping Mats at PAST Outdoors
When you shop with us, you're not just buying a sleeping bag, you're getting a team who has genuinely tested this gear and will help you choose the right one the first time. Browse our full range online or drop into our Helensburgh store, and let's get you set up for your next adventure.
What's the main difference between the Spark and the Spark Pro?
The Spark Pro uses higher fillpower down (900+ vs 850+) and a Free-Flow Zip system that lets it open flat like a quilt, making it lighter and more versatile. It's only available in -1°C and -9°C ratings, while the Spark covers four temperature ratings from 7°C to -18°C.
Do I need a sleeping mat with either of these bags?
Yes. Both bags are tested assuming an R-value of 5 or higher on your sleeping mat, so a good mat is essential to hit the rated temperature and to keep your down insulation performing properly.
What's your return policy on sleeping bags?
We offer a 30-day risk-free return window. Products must be unused and in their original packaging.
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