• Weight (regular) 665 grams
  • Recommended Maximum User Height 170 cm
  • Female Comfort Rating -4
  • Male Comfort Rating -10
  • Cost $799.99

Sea to Summit Flame FMIII Women’s Sleeping Bag Regular

Sleep Systems-Women


Rating: 9 / 10
Weight 1.9 / 2
Value for Money 1.7 / 2
Durability 1.7 / 2
Warmth 1.9 / 2
Versatility 1.8 / 2

Sea to Summit Flame FMIII Women's Sleeping Bag Regular Review

I have been thinking about a new sleeping bag for a while now. As cozy as I am in my sleeping bag, I have been looking for a lighter option that provides the same warmth. My search has been a long one and recently I had the opportunity to test out the Sea to Summit Flame FMIII Women’s Sleeping Bag. Jumping to the end, I love this bag.

Sea to Summit is one of a growing number of companies that use ‘ethical down’ which is a polite way of saying they don’t pluck down off living birds. This does increase the cost but is clearly a more a humane way of collecting the down. The down is also hydrophobic which means it repels water so if it gets wet, it will still keep you warm. The Flame FMIII Women’s bag is filled with 850+ loft goose down and will keep you warm down to -4° Celcius. I took this bag down to 0° Celcius, wearing just a singlet and underpants, and was so warm that several times during the night I had to stick my arms out of the bag or undo the zip.

I tested the regular-sized bag which size-wise suited me well. I’m at the low end of average height (no, I’m not short!) so if you are tall, then the long version is best for you. The shape is ‘mummy’ style and contoured to the female body which means that it tappers in the leg area and down to the feet. This reduces the amount of air in the bag that you need to heat. I’m not usually a fan of the mummy-style sleeping bags given I tend to feel a little too constricted but I didn’t feel that way with the Flame.

The Flame FMIII is the twin to the Spark SPIII series which is classed as unisex but tends to be sold to males. The main difference between the two is a difference in length and width with the Flame series being slightly wider in the hip area, narrower at the chest and having an extra degree of warmth aimed for women who from a physiological perspective, tend to feel the cold more than men. However, I’d ignore the gender descriptions on these bags and choose the model that best fits your personal dimensions and cold tolerance. If you are a male, then this bag will take you down to -10° Celcius.

The Flame FMIII is grey in colour with an orange lining. I’m used to the lighter colour of the sleeping bag being on the inside so I did find this a bit confusing and is why I use a Sea to Summit bag liner to keep my sleeping bag cleaner for longer. When I first got this bag out of the storage sack I thought there were stains on it but it’s just that the shell is almost translucent and so the darker colour down shows through. As an ultralight bag, the outer and inner shell use very lightweight materials (7 Denier Nylon shell and lining fabric) so if you are really rough with your gear then there is potential for you to tear the bag. This is not a bag to loan to a novice hiker friend or use as a hire bag!

The Flame FMIII is a high-end bag. It has draft tubes at the front and back of the neck as well as along the zip to minimise airflow. The zip on this bag is 2-way full-length and there isn’t a toe box zip to allow the bag to flatten out into a quilt like many of the heavier grade bags. The other thing missing is an internal security pocket for a wallet or phone – this doesn’t worry me too much.

Sea to Summit includes a design feature on all its higher-end bags – horizontal down baffles on the upper body and vertical down baffles on the lower body. This means the correct amount of down is kept in the right area of the bag to keep you warm. The hood on the Flame FMII fits close – a result of the weight savings during the design process. I’m used to a more generous hood but the smaller size on the Flame didn’t concern me as much as I thought it may.

The Flame FMIII packs down to a very tiny size and weighs just 665 grams (regular size). Given sleeping bags are often one of the heaviest and bulky items you will carry in your pack, this bag is a real weight and space saver.

I really like this sleeping bag but there are a few negatives. For many, the biggest negative is the cost at AUD $799.99 RRP for the regular size, this is an expensive bag. You can find it on sale at under AUD $700 but that’s still a decent investment. I’ve previously already mentioned the lightweight materials used in the construction which mean you need to ‘handle with care’.

Despite the negatives, this is a great bag if you are looking for a super warm, super lightweight sleeping bag. I’m now saving my dollars to make my purchase!

We Like

  • Women’s specific contoured mummy shape that minimises airflow to keep you warm 
  • 850+ Loft ULTRA-DRY Down provides great insulation and keeps the packed size very small
  • A combination of vertical chest baffles and horizontal lower body baffles that keep the down in the right places to prevent cold spots
  • Full side zip with two sliders provides easy access and extra ventilation options
  • The price! This bag is great for warmth but it isn’t cheap
  • Zipper draft tube, and hood and front neck draft collar prevent warmth being lost

We Don't Like

  • Handle with care as the outer and inner shell are lightweight and potentially fragile if you are too rough
  • The drawstring toggle on the neck is a bit small for people with bigger hands. A slightly larger toggle would improve the ease of use particularly on those cold nights when your hands aren’t working so well
  • Not really a year-round bag, best for cool to cold conditions
  • No foot box zip which limits the versatility of the bag

Best Uses

  • The perfect bag for ultralight hikers and anyone who wants maximum warmth and minimum weight

Buy One

You can purchase the Sea to Summit Flame FMIII Women’s Sleeping Bag Regular from Snowys, Wild Earth, 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!


AUD $799.99 RRP. Keep an eye out for the sales and you may get a great deal on these excellent bags

Other Versions

Sea to Summit Flame series includes other comfort options:

Sea to Summit Flame FMIII Women’s Sleeping Bag Regular

Sea to Summit Flame FMIII Women’s Sleeping Bag Regular temperature ratings. This bag will suit the ‘average female’ down to -4° and the ‘average male’ down to -10° Celcius

1 litre water bottle up against the sleeping bag in its compression bag

Neck and zip baffles

Translucent inner shell

Translucent outer shell

Gill inside the Sea to Summit Flame FMIII Women’s Sleeping Bag Regular


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

Last updated


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