Best cot bed mattresses
For a cot mattress, safety guidance decides most of the specification, and the choice between good products is narrower than the marketing suggests.
I earn a commission if you buy through some links on this page. It never changes what I recommend, and I publish negative verdicts on brands I earn from. Editorial independence.
Safer sleep comes first
UK safer sleep guidance is consistent on the essentials: babies sleep on their back, on a firm, flat, waterproof mattress, in a clear cot with no pillows, duvets, cot bumpers, pods or loose bedding.
The Lullaby Trust is the authoritative UK source and is worth reading directly. Your health visitor or midwife can answer questions about your own situation, which a product page cannot.
That guidance removes most of the decisions. A cot mattress must be firm rather than comfortable in the adult sense, flat rather than contoured, and sized so there are no gaps.
What is left to choose is the core material, whether it is waterproof, and whether it can be cleaned properly. That is genuinely the whole list.
The picks
The pick, if you want one answer
Simba Hybrid Cot Bed Mattress, 7.8 / 10. Firm, flat and properly waterproof, with a spring core that lets the mattress dry out rather than holding moisture.
| Product | Best for | From | Score |
|---|---|---|---|
| Simba Hybrid Cot Bed Mattress | Best overall | Mid range | 7.8 / 10 |
| Panda Bamboo Cot Mattress | Best for washability | Mid range | 7.7 / 10 |
Simba Hybrid Cot Bed Mattress: Best overall
Mid range · 7.8 / 10
The highest scoring cot mattress on this site at 7.8. A spring core keeps the surface firm and flat while letting air move through the mattress, which matters because a cot mattress deals with a great deal of moisture over two or three years.
Buy it if
You want a firm sprung cot mattress from an established UK brand.
Do not buy it if
You need the cheapest option that meets the standards, which is a legitimate choice.
Read the full Simba Hybrid Cot Bed Mattress review
Panda Bamboo Cot Mattress: Best for washability
Mid range · 7.7 / 10
Cleaning is the thing that actually matters day to day. A removable cover washable at 60 degrees is worth more than any fill claim, because 60 is what kills dust mites and 40 only removes allergen. Check the care label rather than the marketing.
Buy it if
You want a removable washable cover, which you will use more often than you expect.
Do not buy it if
You want the simplest possible product.
Read the full Panda Bamboo Cot Mattress review
Measure the cot, not the mattress
The gap rule
The mattress must fit the cot with no gap you could fit two fingers into at any edge. Gaps are a trapping hazard.
Measure the inside of the cot base, length and width, and buy to that. Do not assume a standard size fits: cot dimensions vary between manufacturers, and secondhand or older cots vary more.
Common UK sizes are roughly 120 by 60 centimetres for a cot and 140 by 70 for a cot bed, and those are starting points rather than guarantees. Check depth too: most cot mattresses are 10 to 12 centimetres, and a thicker one raises the sleeping surface, which matters as a baby becomes able to pull up.
Firm means firmer than you expect
An adult reading a cot mattress specification is usually surprised by how hard it feels. That is correct rather than a compromise.
A firm, flat surface is what safer sleep guidance calls for, and softness that would feel pleasant to an adult is not appropriate in a cot. Do not add a topper, a mattress protector pad, a pod, a nest or a sleep positioner to make it softer.
The same applies to the shape. The mattress should be flat, not contoured, raised or wedged, unless a clinician has specifically advised otherwise for a medical reason.
Waterproof, and cleanable, because both are separate things
Waterproof means the core is protected from liquid reaching it. That is a safer sleep requirement rather than a convenience.
Cleanable means the surface you can reach can actually be washed. A removable cover washable at 60 degrees is the practical version of this, and it is what you will use.
The two are not the same product feature, and a mattress can have one without the other. Check both.
Secondhand mattresses, honestly
Safer sleep guidance advises using a new mattress for each baby where possible. If a mattress is reused, the guidance is that it should have been protected by a waterproof cover throughout, have no cracks or tears, be firm and flat with no sagging, and be thoroughly cleaned.
This is a judgement for each family and the guidance exists because the research on reuse is not settled. The Lullaby Trust sets out the position in full, and a health visitor can discuss your own circumstances.
A cot frame passed down is a different question from a mattress passed down. Frames are generally fine if undamaged and the gap rule is met.
What not to use in a cot
Pillows, duvets, cot bumpers, pods, nests and sleep positioners. Safer sleep guidance is clear that the cot should be clear.
A topper or a quilted pad to soften it. Firm is the specification, not a compromise.
A mattress that leaves a gap at any edge. Measure the cot base.
A contoured or raised mattress, unless a clinician has advised it for a specific reason.
Anything marketed as reducing risk beyond the standard guidance. Follow the guidance itself, from the Lullaby Trust and your health visitor.
Also considered, and why they are not here
A roundup is only as useful as what it leaves out, so here is what was assessed and rejected for this list.
| Product | Why it is not on the list |
|---|---|
| Panda Baby Pillow | Not a cot mattress, and named here because it is the most important thing on this page: pillows are not recommended in a cot. Pillow use starts much later, around 18 months at the earliest, and later is fine. |
| Simba Hybrid Kids | For a child in a full-size bed rather than a cot. Different product, different stage, and a sensible next step once the cot is outgrown. |
How this list is made, and who made it
Independence
No brand pays to appear on this site and no placement is sold. Some links earn a commission if you buy, which never changes a score, an order or a verdict. Several of the lowest scores here are on products that carry commission, and several recommendations carry none.
Who writes this. Kyle Klinkradt has worked in the mattress and bedding industry for over ten years across retail, distribution and brand partnerships, and has handled, sold or assessed products from every major UK bed-in-a-box brand. Every review on this site is written by one person, so the scores mean the same thing from page to page.
What the assessment is. Construction specifications against what they physically do: spring height and where in the mattress it sits, spring count for the size, gauge, whether the base is sprung or foam, foam density where it is published, comfort layer depth and material. Then the commercial terms that decide what you are actually buying: trial against returns policy, guarantee length against the company's UK trading history at Companies House, and the regulatory record.
What it is not. This is not a laboratory. I do not publish pressure-mapping data or claim to have slept eight years on every mattress here, because nobody has and pages that imply otherwise are not telling you the truth. Where a judgement rests on construction rather than long-term use, the review says so.
What gets a product removed. Leaving the UK market, a specification change that makes the review inaccurate, or a corrected fact. Brands that have withdrawn are kept on the site with the score removed rather than quietly deleted, because people still search for them.
See editorial independence, corrections and the author page.
How these were chosen
Every product here has its own review on this site with a score out of 10, and the score is a judgement rather than an average. Nothing appears in a list because it pays more.
A score is against the market, not against its own range. The cheapest mattress in a lineup is usually priced to make the model above it look reasonable, and the flagship of a budget range has risen into a bracket where better brands compete. Both are judged against what else you could buy for the money.
Everything listed can actually be bought in the UK. That is not a given: Casper withdrew in July 2020 and Leesa no longer sells here, and both still appear in current British roundups with affiliate links attached.
I do not pad the list. Where only three or four products genuinely qualify, there are three or four. A list of seven when the category contains four good ones is a list with three bad recommendations in it.
Prices move constantly. Judge the cash price on the day rather than any percentage beside it. See every review on this site or where the real savings are.
Questions people ask
How firm should a cot mattress be?
Firm enough that an adult finds it hard. UK safer sleep guidance calls for a firm, flat, waterproof mattress, and softness that would feel pleasant to an adult is not appropriate in a cot. Do not add a topper to soften it.
What size cot mattress do I need?
Measure the inside of the cot base rather than assuming a standard size. The mattress must fit with no gap you could fit two fingers into at any edge, because gaps are a trapping hazard.
Can I use a secondhand cot mattress?
Safer sleep guidance advises a new mattress for each baby where possible. If reused, it should have been protected by a waterproof cover throughout, have no cracks or tears, be firm and flat, and be thoroughly cleaned. The Lullaby Trust sets out the position in full.
Does a baby need a pillow in a cot?
No. Pillows, duvets, bumpers, pods and positioners are not recommended in a cot. Pillow use starts much later, around 18 months at the earliest.