Simond
Simond MT500 folding foam trekking mat (180 x 55 cm)
Where it fits
- Also works for
- Backpacking and wild camping
- Not for
- Bikepacking, Winter mountain
Why these labels
- Backpacking and wild camping: Light to carry: 0.4 kg
- Bikepacking: Bulky for bike bags: packs to 11.5 litres
- Winter mountain: R-value 2.1: too little insulation on frozen ground
From the maker's stated use and the published specs.
- Summer wild camp: 5/10 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. Below this trip's minimum: 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: 9/10 How much it adds to your pack, compared with the whole market.
R-value 2.1 (ASTM).
Cheap summer and mild-weather wild camps where weight matters more than comfort
- Type
- Foam
- R-value
- 2.1 (ASTM)
- Weight
- 370 g (180 x 55 cm)
- Thickness
- 2 cm
- Size
- 180 x 55 cm
Packed size 11.5 L, 55 x 15 x 14 cm Compare with a 2-litre bottle
About two 2-litre bottles long and about one and a half times as wide. Drawn to scale.
Where to buy
Decathlon UK £16.99 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 3/10How well it stops the cold ground chilling you. 3: Below average. Fine for some trips, not others.
Decathlon quotes an ASTM F3340-18 R-value of 2.1, in the R 2–2.9 band: summer and mild nights only (Decathlon itself says above 5 °C).
Thickness
From maker's figures 2/10How deep it is. Deeper is comfier, above all for side sleepers. 2: A weak point.
2 cm thick.
Quietness
Estimate from maker's specs: foam mats make no noise 8/10How little it crinkles or squeaks when you turn over. 8: Clearly better than most.
A foam mat makes no noise when you turn over.
Weight
From maker's figures 9/10How much it adds to your pack. 9: Among the best you can buy for this.
370 g (Decathlon's headline and detail figure) is under 400 g, the top band; one generic spec table on the same page shows 0.35 kg, which lands in the same band.
Packed size
From maker's figures 1/10How much room it takes in or on your rucksack. 1: A real weak point.
Decathlon states a packed volume of 11.5 litres, in the 7 L+ band; its folded size of 15 x 14 x 55 cm works out at 11.6 L as a box (15 x 14 x 55 = 11,550 cm3), so the two agree. It is light but bulky and usually strapped outside the pack.
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) 7/10How comfy it is, including for side sleepers.
2 reviews on comfort, e.g. "The texture and thickness of the mat made it a lot more comfortable than my previous (flat) roll mat.".
Durability*
Estimate: only 2 reviews about durability (fewer than the 3 we need, so never above 8) 8/10How well it resists punctures, leaks and worn valves over seasons of use.
2 reviews on durability, e.g. "Tough as nails.".
In short
Good for
- Cheap summer and mild-weather wild camps where weight matters more than comfort
- Adding warmth and puncture protection under an air mat in spring and autumn
- Duke of Edinburgh-style groups kitting out several people on a tiny budget
Strengths
- Very light at 370 g and cheaper than almost any rival
- Can't puncture or leak, so there is nothing to fail in the night
- Folds up like a concertina and doubles as a seat or a half-length pad
- Two stacked give roughly double the insulation for colder nights, according to a long-term owner
Weaknesses
- Bulky when folded (11.5 litres), so it normally has to be strapped to the outside of your rucksack
- R 2.1 is only fine for summer and mild nights, not for frosty ones on its own
- Only 2 cm thick and firm: basic comfort, side sleepers will feel the ground, and a long-term owner finds it harder than the Therm-a-Rest Z Lite Sol
- At 180 x 55 cm it feels short and narrow to tall people
Sources
We haven't tested this ourselves. Every score comes from these specs, tests and reviews.
ShowHide sources (4)
- Decathlon UK: Simond trekking folding foam mattress 180 x 55 cm, MT500 (product page and specs)
- Decathlon UK customer reviews: folding foam mattress MT500 (923 reviews)
- Sportspullentesters: Forclaz Opvouwbare Schuimmat MT500 review (Dutch)
- Doppelknoten: Therm-a-Rest Z Lite vs Decathlon Trek 100 long-term comparison (German video; Trek 100 is the earlier name of this mat, Decathlon product 174619)