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- Affordable
- Excellent motion isolation
- Supportive
- Edge support isn’t great
- Not a great pick for really hot sleepers
Simba started making mattresses back in 2002, being one of the first bed-in-a-box brands to sell vacuum-packed and rolled mattresses in the UK. Best known for its hybrid mattresses (the Simba Hybrid Pro is one of our best mattress picks), Simba’s latest mattress, the Simbatex Cool, is sold exclusively through Amazon and is a cheaper, all-foam alternative.
That’s all very well and good, but is the mattress actually comfortable to sleep on? I tried it out over a hot summer in 2026 and, despite its name, it’s not the best fit for really hot sleepers. That said, there’s a lot to like about the Simbatex. Read on to find out all about this new mattress on the block.
Simba Simbatex Cool mattress: What you need to know
Design
The Simbatex is an attractive mattress, finished neatly in Simba’s signature blue and grey. It’s a simple design, with several layers of CertiPUR-certified foams: up top there’s a soft and breathable zip-off cover, followed by a layer of the brand’s “Simbatex“ foam. This is an open cell, graphite-infused foam designed to allow air to circulate around the mattress, while also providing cushioning.
Underneath this are two more foam layers: a flat “foam support layer“ and a ridged “7-zoned foam base“. All told, the Simbatex Cool is 23cm deep.
Price and competition
The Simbatex Cool comes in five sizes, starting with a single at £349. This rises to £379 for a small double, £399 for a double, £429 for a king and £479 for a super king. This pricing is similar to that of the DreamCloud Hybrid that I reviewed recently: this also costs £349 in a single, rising to £499 for a double.
The Simbatex is considerably cheaper than even Simba’s most affordable hybrid, the Hybrid Essential, which retails for £799 for a double. The Hybrid Pro, one of our favourite mattresses in Simba’s lineup, costs £1,299 in the same size, while the all-natural Hybrid Apex is a whopping £2,199.
It’s also a competitively priced option compared to some of its all-foam rivals. It’s £50 cheaper than the Nectar Classic Memory Foam mattress (£449 for a double) and Tempur’s ‘entry-level’ Ease mattress (£849).
Since the mattress is sold through Amazon, there’s a good chance that you’ll find it discounted – particularly during deals events such as Amazon Prime Day and Black Friday. Since its launch, I’ve already spotted it on offer for 20% less, bringing a double down to just over £319.
Buying a mattress through Amazon can be a risky business when it comes to sleep trials and returns but the Simbatex comes with Simba’s full 200-night sleep trial and a 10-year guarantee. That’s incredibly generous for a mattress at such a reasonable price.
Delivery
As a bed-in-a-box mattress, the Simbatex arrived rolled and vacuum-packed. Delivery is free, and takes around three days.
After unpackaging, it was ready to sleep after around six hours, but I’d recommend allowing 24-72 hours for it to expand fully. As it’s an all-foam mattress, you should also expect some off-gassing and I did notice the smell for a few days. I should add, however, that I have a rather keen nose though.
How I tested the Simba Simbatex Cool mattress
There’s no greater test for a mattress than actually sleeping on it. This allows me to assess factors such as comfort, support, temperature regulation and motion isolation. I also consider value for money by comparing the mattress’ price to those of its closest competitors.
As anecdotal testing isn’t sufficient on its own, I also run standardised tests to obtain objective data that can be compared across all mattresses tested at Expert Reviews. I gradually place four 2.5kg weights on the bed, measuring the sinkage as I add more weight. I do this at shoulder height and at three inches from the edge of the bed. I also measure how much the total 10kg of weights causes the edge of the bed to tilt.
I carry out two tests with a digital thermometer – one for body heat and another using a heat pad – to see how much the mattress retains heat. For the former, I sit on the mattress with the thermocouple probe placed underneath me, until the thermometer reaches 30°C. After getting up, I then record the temperature decrease at one minute intervals for ten minutes. The heat pad test follows a similar process. After heating up the pad in boiling water, I place it on the surface of the mattress to heat it up. Once the temperature has stabilised and fallen to 50°C, I remove the heat pad and, again, record the temperature at one minute intervals for ten minutes.
Comfort and performance
Our standardised tests
I started by testing sinkage at shoulder height, measuring a drop of 13mm under 10kg of weights. Moving the weights to three inches from the edge of the mattress gave a measurement of 12mm.
I was quite impressed by these results. That’s less sinkage than some hybrid mattresses I’ve reviewed. For instance, the aforementioned DreamCloud Hybrid dipped 21mm in the centre and 20mm at the edge. I would have expected a bigger dip from an all-foam mattress, which suggests that these foams have some heft to them!
It was still pretty hot when I tested the Simbatex, with a room temperature of 28.5°C. It’s worth bearing this in mind when considering the results of my temperature tests. Firstly, the body temperature test saw the heat drop from 30°C to 27.8°C after three minutes, where it lingered for the full 10 minutes.
Meanwhile, the heat pad test saw temperatures drop from 50°C to 29.1°C after three minutes, before dropping further to 27°C after 10 minutes. For context, the Simbatex Cool didn’t lose heat quite as quickly as the Tempur Pro Plus SmartCool mattress (another all-foam option) that I tested recently, although this was reviewed in a cooler room at 23.4°C and costs considerably more at £2,599 for a double. Results were, however, more in line with the DreamCloud Hybrid, which was tested in an equally hot room at 29°C.
Is it comfortable?
Considering the Simbatex Cool is an all-foam mattress, I was actually quite surprised by how firm the Simbatex is. Simba quotes a “medium firm” feel, which I’m inclined to agree with. However, it still offered plenty of cushioning around the hips and shoulders. Both my husband and I thought it was particularly suited to back sleepers: he found it offered ample support. While I agreed, I would have liked it to be a little firmer in the lumbar region, which is something I’m quite fussy about.
Both me and my husband are quite lightweight, and we both thought the Simbatex was a little too firm for sleeping on our sides. However, after a couple of weeks on the mattress I could feel the foams starting to soften, which leads me to believe that it would be more accommodating to side sleeping over more time. On the other hand, average and heavier side sleepers should find it comfortable from day one. I don’t recommend this mattress to stomach sleepers though, as the foams don’t offer quite enough support around the hips to keep the spine aligned.
Temperature regulation
With “cool” in the name, you might expect this mattress to be a great fit for hot sleepers. However, perhaps because it’s all-foam, it’s a bit disappointing in this respect. The brand says that Simbatex foam has five times more airflow than standard memory foam and while it is breathable, my husband – the resident hot sleeper – didn’t find that the mattress kept him cool overnight. He felt quite clammy within about an hour of lying on the bed.
As someone of a more reptilian nature, I didn’t have much of an issue with overheating. As a general rule, however, I wouldn’t recommend an all-foam mattress to those who sleep hot.
Motion isolation and edge support
All-foam mattresses often have far better motion isolation than their hybrid cousins, due to the lack of springs. The mattress did an excellent job of removing motion transfer and I barely felt my husband or foster cat moving about during the night.
Edge support, on the other hand, is a little lacking. When I sat on the edge of the bed, I felt a rather profound sinkage. This wasn’t so pronounced when sleeping, but I suspect that heavier bodies might not feel quite as secure.
Verdict
The Simba Simbatex Cool is excellent value for money and offers many of the features for which the brand is respected. It’s comfortable, with plenty of cushioning to support pressure points and I think back sleepers and side sleepers of average/heavier weight will like it from day one. Motion isolation is also particularly impressive, which is ideal if you’re a restless sleeper or share your bed with one.
However, edge support is lacking, and I wouldn’t recommend this mattress if you’re a very hot sleeper as the all-foam construction just can’t shift the build-up of heat as well as a hybrid mattress.
That said, if you’re on the fence, the generous 200-night trial – the length of which I’d usually expect from a more expensive mattress – is very welcome for such an affordable option. If you’re on a budget, and you’re not dissuaded by my caveats about edge support and temperature regulation, you’d do very well to put the Simbatex near the top of your list.
