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Combining memory foam with the company’s Aerocoil springs, the Simba Hybrid Pro is a bed-in-a-box that delivers the highest levels of comfort. In my tests, I found the mattress firm but supportive in all positions. Thanks to the internal design and layer of wool, the Hybrid Pro also rids any build up of heat quickly. Its deepness and the lack of a removable cover are two minor downsides.

Simba was one of the pioneers of the mattress-in-a-box revolution. The Simba Hybrid Pro goes beyond a basic memory foam mattress, adding a layer of springs for extra comfort.

Delivering excellent support in all of my tests, plus the ability to reduce heat retention, the Hybrid Pro is a fine high-end mattress. A removable cover would have been welcome; but this minor issue aside, the Hybrid Pro is a top-choice mattress.

Simba sells the Hybrid Pro in a variety of sizes to suit almost any bed type, including Single, Small Double, Double, EU Double, EU Queen, King and Super King. I’ve listed the sizes and base prices below, although there are often large discounts available that will reduce these costs.

All mattresses are delivered within three days of ordering and come with a 200-night trial period. If you don’t like the mattress at any point during this period, Simba will send a two-man team to collect it for free. Fortunately, Simba doesn’t expect you to repackage the mattress. And if you do decide to keep the mattress, it comes with a 10-year guarantee against defects.

The mattress arrives wrapped in plastic, inside a cardboard box. Note that it may require two people to handle the unboxing and unwrapping of larger mattress sizes.

As is the case with other brands of mattress-in-a-box, the Simba Hybrid Pro has to be left to expand once it’s free from its wrapping. It takes around six hours before you can use the mattress, so I found it best to unpack mine in the morning, giving it the day before I put on the sheets.

Although the Hybrid Pro is available in a range of sizes, all are a chunky 28cm deep – so make sure your fitted sheets are deep enough to cover it. The combination of my bed height and mattress height made me feel like I had to climb into bed; that’s alright by me, since it feels more luxurious to recline at such a height.

This mattress comes encompassed in a soft, breathable cover – or sleep surface, as Simba calls it.

There’s a zip that lets you open the cover, but this is used in manufacturing only; you can’t actually remove the cover for washing as you can with the Emma Original. As such, I’d advise that you invest in a mattress protector for this mattress, and Simba sells a matching model.

Internally, the Hybrid Pro is made up of six layers – making for a sum total of seven including the sleep surface). First up is the wool layer, which is good for allergy sufferers, and will either help to keep you cool or warm, depending on the season.

Next, there’s the Simbatex foam layer, which the company infuses with graphite, using an open-cell design to increase airflow to prevent overheating – a common issue with regular memory foam mattresses.

There are then two layers of Aerocoil springs, built to support your body, while also increasing airflow.

Next comes a harder edge support layer, so that the Simba Hybrid Pro will continue to provide support for those who tend to sleep close to the edge of the bed.

Finally, there’s the chunky multizone foam base that gives the mattress its depth and final layer of support.

This layering means that, like most modern mattresses, the Simba Hybrid Pro shouldn’t be turned over. However, Simba says that the mattress should be rotated once a month for the first three months, and then every three-to-six months thereafter. This helps to maintain the quality of the mattress, preventing any dips or sagging.

Again, turning such a beast of a mattress may require two people: I was grateful for the handles on the side of the mattress, which made this job easier.

To test mattresses, I take measurements in various key positions to see how far I sink in, while also gauging the level of support.

Sitting on the edge of the Hybrid Pro, I measured a drop of just 5.5cm. That’s around half of the 10cm drop on my old memory foam-topped pocket-sprung mattress. In practice, it means that the Simba Hybrid Pro provides support right up to the edge. In fact, I never felt as though I would slide off the edge – which is great, given the height from which I’d fall.

Next, I measured the drop when sitting up in bed reading. My old mattress was too soft – I sank 8cm into it. The Hybrid Pro proved much better, with just a 3cm drop. Sitting up on the Simba Hybrid Pro is like sitting on a comfortable sofa.

I then moved to the standard sleeping position. Lying on my back, I measured the impact on my hips at 4cm and shoulders at 1.5cm, helping keep my spine aligned. Moving onto my side, I measured a dip of ****4cm at my hips and 4.5cm at my hips**** CHECK FIGURES BECAUSE BOTH MEASUREMENTS SAY “HIPS” PLUS THEY”RE MUCH CLOSER THAN THE FIRST SET*****; again, a good level of support, keeping my spine aligned. My old mattress dipped by more than 7cm at both points.

Sleeping on my front, I measured the dip at my stomach of just 5cm, showing a firm level of support.

Overall, I have found the Simba Hybrid Pro quite a firm mattress, but the support and comfort on offer are excellent. Those who prefer a slightly softer option may be better looking elsewhere. However, while this mattress is firm, it isn’t uncomfortable or like sleeping on a plank.

To evaluate the mattress with two people sleeping side by side, I used an accelerometer placed in the position of a second sleeper to measure movement transferral. First, I started by climbing into bed. The bigger the movements in the graph below, the more movement the accelerometer has picked up. As you can see, there’s a degree of movement, but overall it’s a gentle graph.

Compare the same action on my old bed, and you can see quite a difference, with some readings off the scale.

It’s a similar story for turning over on the Simba mattress. The Hybrid Pro insulates movement well.

The experience on my old pocket-sprung mattress is far worse; I could feel every movement of my partner through the night.

With the Simba Hybrid Pro’s excellent motion insulation, a restless partner won’t ruin your night’s sleep.

A common complaint levelled at memory foam mattresses is that they’re very hot to sleep on, retaining heat to a degree that makes getting a good night’s sleep difficult. To test the Simba Hybrid Pro’s performance in this regard, I laid on my back on the bed for 10 minutes, and then used a thermal camera to evaluate heat retention, timing how long it takes before the mattress returns to its ambient temperature.

Following just two minutes, my outline has faded significantly, as you can see comparing it to the original shot taken just after I stood up.

Once three minutes had passed, my outline appears very close to the surrounding temperature of the mattress. That’s super-quick heat dissipation and impressive performance. With the rival Hyde & Sleep Raspberry mattress, my body outline was still clearly visible through the thermal camera following assessment after three minutes.

If you want a premium mattress that doesn’t get too hot and offers plenty of support, the Simba Hybrid Pro is for you.

If you prefer a mattress with a washable cover, then look elsewhere.

The Simba Hybrid Pro is one of the more expensive mattress-in-a-box model, but it’s money well spent. Proving supportive with excellent heat dissipation, it helps you achieve a good night’s sleep, no matter the season. It’s super-deep and more on the firm side, so those looking for a more compact choice or a mattress that’s softer may want to look elsewhere.

Unlike other sites, we test every mattress we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.

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Used as our main mattress for the review period

We use a thermal camera to see how quickly the mattress can dissipate heat for a comfortable night’s sleep.

We measure how far we sink into the mattress in various positions to measure support levels.

We use an accelerometer to measure how movement from one person is transferred to the other side of the bed.

Measuring the dip at hips and shoulders, this mattress proved supportive for side sleepers.

Yes – it needs around six hours to reinflate before you can sleep on it.

No, you should really buy a mattress protector to use with it.

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We also expect our journalists to follow clear ethical standards in their work. Our staff members must strive for honesty and accuracy in everything they do. We follow the IPSO Editors’ code of practice to underpin these standards.

Founded in 2004, Trusted Reviews exists to give our readers thorough, unbiased and independent advice on what to buy.

Today, we have millions of users a month from around the world, and assess more than 1,000 products a year.

Editorial independence means being able to give an unbiased verdict about a product or company, with the avoidance of conflicts of interest. To ensure this is possible, every member of the editorial staff follows a clear code of conduct.

We also expect our journalists to follow clear ethical standards in their work. Our staff members must strive for honesty and accuracy in everything they do. We follow the IPSO Editors’ code of practice to underpin these standards.

Products tested and reviewed since 2003