Plenty of families buy two cot mattresses before their child turns three: a firm one for the baby months, then a kinder one once there's a toddler in the cot bed. The Simba Hybrid Cot Bed Mattress is built so you only buy once. It's Simba's own, sold on its own site, and it measures 140 by 70cm and 10cm deep, with a firm, flat face for the first year and a softer face you turn over to from 12 months, both sitting on the same layer of small pocket springs. It is the only cot mattress Simba makes, and it covers birth to three, which is where the brand's Simba Hybrid Kids Mattress takes over. Press a hand into the baby side and it barely gives, which is how I like a cot mattress.
The difference between the two Simba children's mattresses is simple. This one fits a cot or cot bed and turns over as your child grows. The Kids Mattress is a 16cm single for a bed, a bunk or a cabin bed, and it is the one to move on to. Buy this if your cot bed takes a 140 by 70cm mattress and you'd like the second stage sorted on the day you build the cot. Skip it if your cot is the smaller 120 by 60cm size, because this is the only size it comes in.
I'd buy it. Two faces make sense in a cot, where a baby needs firm and flat and a two-year-old does better with a little give, and Simba has put a layer of pocket springs under both. The hybrid build is the thing Simba does best, and it scales down to a cot well.
Firm and flat for the first year, then a softer side
The baby side is a knitted cover, a water-resistant lining and a thick layer of firm Simba Renew over the springs. Renew is Simba's fibre, made from recycled plastic and combed into airy layers, and there's no memory foam anywhere in this mattress. Lay a palm flat on the baby side and push, and the fibre stays level while the springs underneath barely move. Simba's own line for this face is that it "keeps babies 0-12 months flat and straight", and the build is consistent with it: there's no soft layer on top for anything to dip into.
At 12 months you turn it over. On that side your child lies on two 15mm layers of Renew, one medium and one soft and fleecy, over the same springs. With less fibre between the child and the springs, a knee or a hip sinks a touch further before the springs push back, so the toddler side has some give where the baby side has almost none. It's still firm by any adult standard, and that's right for a toddler. I'll always pick a turnable mattress, and on this one the turn is the reason to buy it.
Is the Simba cot bed mattress firm?
Yes, and on the baby side, very. Owners describe that face as very firm and "firm as it should be for a baby", and they're right to be pleased. New, firm, flat and fitting the cot with no gap is everything I look for in a cot mattress, and in a cot bed made for a 140 by 70cm mattress this one ticks all four on day one.
The toddler side is where owners differ. Plenty talk about the mattress growing with their child, firm for the baby and soft enough to grow into. One parent whose two-year-old sleeps on the toddler side called it "rock solid" and said they wouldn't want a night on something that hard themselves. I'd take that as a point in its favour. Most good toddler mattresses feel firm to an adult hand, and I would much rather a growing child slept on firm than on soft.
648 small springs, and in a cot I'm glad of them
Under both faces sit 648 conical Aerocoil springs, each 20mm tall in its own pocket, made from high-carbon steel in Leeds. On an adult bed I'd call springs that short padding and ask where the full-height unit had gone. A 10cm cot mattress has no room for a full-height unit, so these are what give both faces pocket-spring support under the fibre, and what gives the toddler side its bit of bounce. Small conical springs are the part of Simba's hybrids I rate most, and it's good to see them in something this size. Depth is a different conversation on a cot, too: 10cm is normal here, and I wouldn't want more.
Measure inside the cot before you order
Simba's fitting rule is plain: "The maximum gap between the mattress and any sides/ends of the cot should not exceed 30mm." Measure inside your cot bed from rail to rail, lengthways and across, before you order. Owners say it sits snugly, one with "no gaps down the sides or both ends", and a few found it a squeeze to lower into the cot, one of them to stretch a fitted sheet over too. Snug is the better side of that line. If your cot leaves a gap wider than Simba's 30mm anywhere, this is the wrong mattress for that cot, however well it's made.
For everything else about how your baby sleeps, from the room to the bedding, go to the NHS and the Lullaby Trust. Their guidance is where I send every parent. Simba says the mattress conforms to BS EN 16890, the British standard for cot and crib mattresses, and asks that you use only one mattress in the cot.
A cover you can wash, and two sides to tell apart
The knitted cover unzips and goes in the machine at 40C. Skip the tumble dryer, biological powder and bleach, and let the cover dry fully before it goes back on. There's a water-resistant lining under the cover on both faces. Owners say it comes well packaged, one of them flat with no bends, and another noticed "no nasty smells" out of the box. They also say the two faces are labelled on the mattress itself, though one couldn't tell which side was meant for which age. Check the label the day it arrives, before the first sheet goes on, and put the firm side up.
Buying once is where the money goes further
A single-sided firm cot mattress does the same job for the first year. What the Simba adds is the second face, and if your child stays in the cot bed until three, that's a mattress you don't need to buy at eighteen months. Parents who'd used a cot mattress from another brand before make the same comparison: one called the difference "worlds apart", and another said the old one had sunk in the middle.
I think Simba's hybrids cost too much for most of the year, and with an adult bed I'd tell you to wait for a sale. With a cot the timing isn't yours to choose, so if there's an offer on when you're buying, take it, and if there isn't, buy it anyway.
What to buy instead
If your cot takes the smaller 120 by 60cm mattress, look at the Relyon Luxury Pocket Sprung Cot Bed Mattress at Mattress Online, which costs less. It's firm pocket springs under soft white fibres, sold there in the 120 by 60cm continental cot size, with one sleeping side and no softer face to turn to. When your child outgrows this Simba at three and moves into a proper bed, the Simba Hybrid Kids Mattress is the next step.
