Rab
Rab Mythic 0 °C Down Sleeping Bag (Regular)
Best use
- Made for
- Backpacking and wild camping
- Also works for
- Bikepacking
- Not for
- Winter mountain
Why these labels
- Backpacking and wild camping: The maker states this use, and the published specs do not rule it out.
- Bikepacking: Small enough for bike bags: packs to 6 litres
- Winter mountain: Comfort rating 5 °C: too cold for winter nights
From the maker's stated use and the published specs.
- Summer wild camp: 7/10 UK, roughly May to September, nights above about 8 °C, sheltered pitches.
- Three-season hills: 4/10 UK hills in spring and autumn. Wind, rain, and nights near freezing. Capped at 4: needs warmth 7+ (comfort 0 °C or colder).
- Winter camp: 4/10 UK winter or high ground. Below freezing, strong wind, possibly snow. Capped at 4: needs warmth 9+ (comfort -5 °C or colder).
- Weight: 10/10 How much it adds to your pack, compared with the whole market.
Comfort 5 °C, limit 0 °C (ISO 23537).
Weight-conscious three-season backpackers who want an ISO-rated bag under 600 g
- Zip
- Short
- Comfort
- 5 °C
- Limit
- 0 °C
- Fill
- 900 fill down
- Weight
- 500 g (Regular)
Packed size 6 L, 30 cm long and 16 cm across Compare with a 2-litre bottle
About as long as a 2-litre bottle and about one and a half times as wide. Drawn to scale.
Where to buy
Alpinetrek £374.96 In stock. Free delivery. Regular, left zip.
View at shop: AlpinetrekUltralight Outdoor Gear £424.99 In stock. Free delivery. Regular. This shop's page lists 519 g and an RRP of £499.99.
View at shop: Ultralight Outdoor GearRab £500 In stock. Free delivery. Regular, left zip.
View at shop: RabPrices checked 8 Nov 2026 on each shop's own page; shops can change them. We earn no commission on these links; shops are listed by price. More
Our ratings (out of 10)
1 to 10, compared with the whole market. Each says what it's based on. How we score
Warmth
From maker's figures 5/10How cold a night you can sleep comfortably through. 5: Does the job. Average for wild-camping gear.
Rab's ISO 23537 comfort figure is 5 °C (limit 0 °C, extreme -15 °C), in the 0.1 to 5 °C band. The 0 °C in the name is the limit figure, not the comfort figure.
Room inside
Estimate from maker's specs: maker's shoulder girth (fewer than 3 reviews about room) 6/10How much room to move, bend your knees and sleep on your side. Roomier is comfier. 6: A bit better than average.
No review we found says how roomy it is, so this is an estimate from the maker's shoulder girth.
Weight
From maker's figures 10/10How much it adds to your pack. 10: The best you can buy for this.
Rab gives 500 g for the Regular, under 700 g. One UK shop lists 519 g, which is still in the same band.
Packed size
From maker's figures 6/10How much room it takes in your rucksack. 6: A bit better than average.
Rab gives only two figures, 30 x 16 cm, so it's a stuff sack and we take the smaller one as the width: 3.1416 x 8 x 8 x 30 = 6,032 cm³, so 6.0 L, just inside the 6–8.9 L band.
In short
Good for
- Weight-conscious three-season backpackers who want an ISO-rated bag under 600 g
- Spring to autumn camps in the UK with nights down to about 5 °C, or a little colder with extra clothing
Strengths
- Packs to about 6 L
- 900-fill down with a hydrophobic finish, hand-filled in Derbyshire
- Helix-shaped baffles are designed to stop the down moving, and a reflective lining adds warmth without weight
- Sidewall baffles give a little more room for side sleepers
Weaknesses
- The 0 °C in the name is the limit rating; the comfort rating is 5 °C, so cold sleepers will want a warmer bag
- Half-length zip saves weight but limits venting on mild nights
- Slim cut, and the 10D shell fabric needs careful handling
- No hands-on reviews of this 2026 bag yet, so damp performance, comfort and durability are 'Not enough evidence'
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.