Simba Earth Apex Mattress review: Firm but fabulous

Our Rating :

Price when reviewed : £1499

Single

A decade ago, saying you had the Simba Earth Apex mattress would have drawn blank faces from my friends and relatives (save possibly for questions about The Lion King). Yet in less than 10 years, the company has gone from a humble ‘bed-in-a-box’ startup to one of the biggest mattress brands in the UK, winning countless awards and scoring hundreds of thousands of five-star reviews online.

But is all the hype worth it? And how would Simba fare should it move away from its highly successful foam-and-spring hybrid models in the quest for a more ecologically considerate construction? The launch of the all-natural Simba Earth range and an opportunity to put the Simba Earth Apex to a long-term test gave us a chance to find out.

I put this top-of-the-range “medium-firm” mattress to the test from June 2024 through to March 2025, with my partner and a couple of visitors sharing their second, third and fourth opinions. Fair to say, that’s a lot to throw at a mattress, so would the Simba Earth Apex hit the top spot for all of us? Read on to find out.

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Simba Earth Apex Mattress review: What you need to know

As I’ve explained, Simba’s Earth range of mattresses are a departure from the company’s original designs, which feature layers of foam, springs and memory foam. Instead, the springs remain, but the foam has been switched out for natural materials that can be easily recycled.

This undoubtedly makes them more eco-friendly, with less of your mattress likely to end up in landfill. The mattress we tested consisted of eight internal layers, encased in a breathable wool and silky viscose. There are four cushioning layers – one each of British wool, Yorkshire hemp and flax, a cashmere-silk-wool mix and a mohair/wool combo. Finally, the base consists of three layers of springs – two layers of micro springs, one “QuadCore” carbon-steel sprung base and a last cushioning layer. According to Simba, its QuadCore springs “are grouped just four at a time, disrupting any ripple effect and limiting motion transfer to encourage more tailored, accurate support”. Something we were keen to put to the test.

Since receiving our test mattress, Simba has ‘fine tuned’ the Earth range, with the Apex now featuring an increased seven cushioning layers (one of Cashgora and silk, five of British wool and a more tightly knit Hampshire wool), and a slight increase of depth from 30 to 32cm.

Unlike early iterations of Simba mattresses, the Earth Apex is delivered flat and wrapped in plastic, rather than in a box, with cardboard protecting the corners. I did feel the thick plastic wrapping went against the eco credentials somewhat, but as it is taken away on delivery (see below), I’d be interested to know if it is reused.

Simba provides a “VIP Delivery Service” for their Earth mattresses, encompassing the full installation of your mattress within your home, the removal of all packing materials and the option to dispose of your existing mattress if needed. Simba used an external company, Rhenus, to manage the delivery, offering online scheduling after our order was placed. They maintained excellent communication through WhatsApp throughout, confirming a three-hour delivery window (1.30-4.30pm) at 7am on the morning of the delivery, and messaging 30 minutes before their arrival to confirm their ETA.

The two-man delivery team arrived on the dot at 1.30pm, and were very polite. They donned shoe protectors before entering the house, and generally took care to manoeuvre the mattress up the stairs to our guest bedroom, heeding my warning that we’d just had the staircase wallpapered. Though they were generally meticulous, one team member employed a somewhat forceful kick to navigate the mattress around a corner, but aside from that, all went smoothly, and no harm was done.

The mattress was ready to sleep on right away – there was no waiting for it to unfurl or ‘decompress’ – and there were no chemical odours. The mattress smelt of very little, save for a very faint lanolin scent that was hardly noticeable.

Simba Earth Apex Mattress review: Key specs

Simba Earth Apex Mattress review: Price and competition

Simba’s Earth Apex is not a budget mattress. Far from it. In fact, it’s one of the most expensive mattresses I’ve ever slept on. When I first received the mattress for review, it had an RRP of £2,449 for a king size. At time of writing, it costs from £1,299 for a single mattress, £1,999 for a double, £2,099 for a king and £2,599 for a super king, so the ‘tweaks’ made to the construction have resulted in a price decrease.

But how does it compare to some of our other top mattress picks? Let’s start with another of our favourites in 2025, the Silentnight Premier Inn 2.0, which costs £749 for a double and £799 for a king – less than half the price, in both sizes. But the Silentnight uses hollowfibre and foam in place of the natural materials, and is not quite as deep as Simba’s quoted 30cm (but more on that later). Simba is certainly expecting you to pay a lot more to avoid synthetic materials.

Looking to its own stable, the Simba Hybrid Pro costs £1,149 for a double – still a hefty £850 less for the same size mattress. And the mid-range Panda Hybrid is even further away in price at £799 for the double.

Looking at the ‘all natural’ market, however, the Simba Earth Apex suddenly looks more competitive. For example, The Woolroom’s premium Holcombe mattress with cashmere, merino wool, mohair and horsehair layers and 3,400 pocket springs costs £4,699 for a double. We’ve also tested Simba’s Earth Source, which is the most affordable in Simba’s all-natural line-up. This costs £1,199 for a double – a very significant £800 less. However, the Source has less than half the spring count of the Apex (2,900 versus 6,700), has fewer layers of cushioning and is 4cm shallower. Given our reviewer, Sarah, felt the Source to be very firm indeed, we believe the Apex will offer a more sumptuous and comfortable sleep experience overall, perhaps justifying the price difference.

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Simba Earth Apex Mattress review: Comfort and performance

For context, my partner and I have always shared a mattress of medium firmness. I’m perimenopausal and tend to sleep quite hot, on my side, while my husband, who has a physical job and suffers from intermittent back pain, tends to mix between sleeping on his side and his back.

Both our visitors suffer from mobility issues, so edge support is extremely important to them. And despite their difference in age (early 30s versus early 60s) both sleep cool and on their side. Our 60-something sleeper also has scoliosis, so back support would be extremely important to her.

My partner and I have been sleeping on this mattress regularly for 10 months now, through hot summer days and cold winter nights, so we’re well placed to make judgments on its long-term performance. But let’s start with first impressions. This is a thick mattress. We measured it at 28.5cm (a tad shallower than the 30cm listed on Simba’s website, but still considerably thicker than the 17cm John Lewis pocket-sprung mattress it replaced). That means you may struggle to cover it with a standard fitted sheet, so we invested in some extra deep ones from Dusk.

The mattress has two handles on each of its longest sides, which are beautifully stitched and feel sturdy – not that they’re there for flipping the mattress, mind you. Due to its construction, these mattresses can only be turned. But we have turned the mattress after six months of use, and the handles made this nice and easy as a two-person job. We can’t yet judge whether not being able to flip the mattress will affect its longevity, but have been impressed by its build quality so far. We’ve not noticed any sagging or decrease in height/plumpness.

Now, to sleep, perchance to dream. Simba describes the mattress as “medium-firm”. There’s no option to choose the firmness of the Apex Earth, as this is specified by the materials it’s made from. Now, I’ve long been used to sleeping on what I’ve thought to be “medium” mattresses, and the Simba instantly struck me as a good deal firmer. Yet as a side sleeper I slept very well and almost instantly noticed that I tossed and turned less at night. And I still ‘sank’ into the mattress enough not to feel the need for a mattress topper. My husband, too, initially perceived the mattress as too firm, but after a couple of nights, he found it surprisingly comfortable, providing both cushioning and good support. However, my 60-something friend said she would have benefited from a soft mattress topper.

Next, to motion transfer. As we’ve mentioned, Simba says its spring set up and design is intended to eliminate motion transfer, and my partner and I can enthusiastically back this claim up. In comparison to our previous pocket spring and foam mattresses, we barely noticed when the other got up in the night, and there were no issues with us rolling into each other unintentionally – handy given we’re used to sleeping in a king-size bed. We decided to put things to the test by placing a half-full glass of water on one side of the mattress. We sat down on the other side, and then got up again gently, as if we were getting up or going to bed while the other was there, and no water splashed out at all. In fact, we saw no significant movement in the water level until we sat within 10cm of the water glass.

Edge support is an extremely important element of a mattress, particularly for our guests with mobility issues, who need a firm mattress beneath them in order to launch themselves up easily, and also so they can sit on the edge to put on socks. And of course for two people sharing a double bed, better edge support buys us a couple of extra centimetres of sleep surface on either side. In all cases, the Earth Apex has been impressive in this regard, and hasn’t lost any of its sturdiness in 10 months. Both our visitors felt well supported sitting at the edge of the bed, though the edges are slightly rounded and there is a little raised piping that meant they found it more comfortable to sit on top of the duvet to change socks and so on, but we were all very satisfied overall.

One final but important point was how ‘hot’ we slept on this mattress. Because it is filled with natural materials, including wool, which is naturally moisture-wicking (able to draw moisture from our bodies, making us feel cool), the omens were good. And again the Earth Apex made true on its promise. On the hottest nights, I never felt like I was overheating. And as I sleep warm, that was a godsend. This is really where the choice of natural materials wins out for me. I’ve always struggled with foam mattresses, and the excess sweat they cause can lead to the mattress becoming stained. But 10 months in, the Earth Apex mattress remains smart and stain free.

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Simba Earth Apex Mattress review: Verdict

While I worried it might be too firm at first, I’ve grown to love this mattress, and it’s aged gracefully so far. It seems to regulate my temperature while still feeling cosy and warm on winter nights. It has enough “give” on the surface that I sink into it while giving me really good support. My other half has found sleeping on it has eased his back pain, and we both find that we toss and turn less in the night. Edge support is excellent for those who need it and there is very little motion transfer – in fact the mattress is truly superb in this regard.

I have just two notes. The first is that the tufts or rosettes on the surface of the mattress do attract dirt and are tricky to clean. And then there’s that high price. But you will sleep soundly knowing that when it’s at the end of its life, you can send it away to be recycled rather than clog up landfill. All said, we can’t deny it’s the best mattress this reviewer has slept on, and would wholeheartedly recommend it if you can afford it.