Simond
Simond MT500 Air Inflatable Trekking Mattress (size L, 180 x 52 cm)
Where it fits
- Also works for
- Bikepacking, Backpacking and wild camping
- Not for
- Winter mountain
Why these labels
- Bikepacking: Small enough for bike bags: packs to 1.7 litres
- Backpacking and wild camping: Light to carry: 0.5 kg
- Winter mountain: R-value 1.5: too little insulation on frozen ground
From the maker's stated use and the published specs.
- Summer wild camp: 6/10 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 5+ (R 3 or more).
- Winter camp: 4/10 UK winter or high ground. Below freezing, strong wind, possibly snow. Below this trip's minimum: needs warmth 7+ (R 4 or more).
- Weight: 7/10 How much it adds to your pack, compared with the whole market.
R-value 1.5 (ASTM).
Summer wild camps and bothy-style trips when nights stay above about 8 °C
- Type
- Air
- R-value
- 1.5 (ASTM)
- Weight
- 510 g (L)
- Thickness
- 5 cm
- Size
- 180 x 52 cm
Packed size 1.7 L, 22 cm long and 10 cm across Compare with a 2-litre bottle
Shorter than a 2-litre bottle and about as wide as one. Drawn to scale.
Where to buy
Decathlon UK £44.99 In stock. Delivery from £2.99.
View at shop: Decathlon UKPrices 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 2/10How well it stops the cold ground chilling you. 2: A weak point.
Maker's ASTM F3340-18 R-value is 1.5, under the R 2 line: summer only, and Decathlon itself says above 8 °C.
Thickness
From maker's figures 5/10How deep it is. Deeper is comfier, above all for side sleepers. 5: Does the job. Average for wild-camping gear.
5 cm thick.
Quietness
Estimate from maker's specs: mat type (fewer than 3 reviews about noise) 5/10How little it crinkles or squeaks when you turn over. 5: Does the job. Average for wild-camping gear.
No review we found says how noisy it is, so this is an estimate from the mat type.
Weight
From maker's figures 7/10How much it adds to your pack. 7: Better than most.
510 g (495 g mat only) sits in the 400–549 g band.
Packed size
From maker's figures 8/10How much room it takes in or on your rucksack. 8: Clearly better than most.
Maker gives 1.7 L packed volume, in the 1.5–2.4 L band. Its folded size, 22 cm long and 10 cm across, agrees: 3.1416 x 5 x 5 x 22 = 1,728 cm³, about 1.7 L.
What reviewers say (out of 10)
Ratings marked * are from reviews and are not part of the trip score. They are reviewers' scores, not our own measurements. How we score
Comfort*
Estimate: only 2 reviews about comfort (fewer than the 3 we need, so never above 8) 8/10How comfy it is, including for side sleepers.
2 reviews on comfort, e.g. "un confort supérieur, surtout sur des terrain caillouteux".
Stability*
Estimate: only 2 reviews about stability (fewer than the 3 we need, so never above 8) 6/10How well you stay on it without rolling off or bouncing.
2 reviews on stability, e.g. "avoid the slight slide between the sleeping pad and the bottom of the tent.".
In short
Good for
- Summer wild camps and bothy-style trips when nights stay above about 8 °C
- Budget full-length mat for hikers who want something more comfortable than a foam roll
- Stacking on a foam mat for a colder night, as one reviewer did
Strengths
- Light at 510 g and packs to about 1.7 litres
- Blows up by mouth in about 8 to 10 breaths, with a separate valve to let air out
- Grippy dots on top help stop a sleeping bag sliding off
- Comes with a self-adhesive repair patch, and Decathlon gives a 2-year warranty
Weaknesses
- Not warm: R 1.5 is summer only, and reviewers say it is no good for cold autumn or winter nights unless you add a foam mat underneath
- Only 5 cm thick, so side sleepers may find it less cushioned than thicker mats; some Decathlon buyers still feel the ground at the hips, and one used two mats stacked
- Air mats can puncture: one reviewer put a poncho under it on thorny or stony ground
- Few independent long-term durability reports: most evidence is from short trips or shop reviews
- A few Decathlon buyers find it fiddly to squeeze all the air out when packing it away
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (5)
- Decathlon UK: Simond Inflatable trekking mattress, size L, MT500, 180 x 52 cm
- Advnture: I pushed budget Decathlon camping gear to its limits (Forclaz MT500 mattress, one cold wet night)
- Olympus Mountaineering: Forclaz MT500 Air Inflatable Trekking Mattress Review
- Le Banquier Randonneur: Matelas gonflable de Trekking MT500 Air de Forclaz (20 nights, XL size)
- Decathlon UK customer reviews: MT500 inflatable trekking mattress, size L (1,599 reviews, 4.5 out of 5)