Safe Baby Mattress: How to Choose (2026 Guide)

Choosing your baby's mattress is one of the first sleep decisions you make for them — and one of those that weighs most on safety. Unlike an adult mattress, the criterion here is not comfort: it is firmness, the fit to the cot, breathability and the materials. In this guide I explain what to check before buying, with the specific figures and certifications you should look for.

— Ana Cristina, Dreamura Sleep Advisor

The six criteria, in brief

If you only read this section, you already have the essentials:

  1. Firmness. The surface has to recover its shape immediately when you press it with your hand.
  2. Foam density ≥ 23 kg/m³. This is the figure that separates a firm, stable foam from one that gives way over time.
  3. OEKO-TEX Standard 100 certification on the fabrics — tested for harmful substances.
  4. The exact size of the cot, with no gap next to the bars.
  5. Breathability of the fabric and the core, to reduce the risk of overheating.
  6. EN 716 standard on the cot, if you are buying cot and mattress together.

Firmness: why it is not like the parents' mattress

An adult may prefer a soft mattress. A baby does not. In the first months, a baby does not yet have the strength to turn their head if it sinks into a soft surface. That is why the recommendation for safe sleep is always a firm mattress, one that keeps the surface flat and stable.

The test I always do: press the palm of your hand into the centre of the mattress and lift it. If the surface returns to flat immediately, it is fine. If a mark stays for a few seconds, it is too soft for a baby.

Dreamura baby mattresses have medium firmness, in line with safe sleep recommendations: the surface stays flat and recovers its shape without sinking.

Density: the figure almost nobody shows

The firmness you feel with your hand tells you about the present. Density tells you about the future. A low-density foam can seem firm in the shop and give way after a year of use — and in a baby mattress that is a safety problem, not a comfort one.

The reference recommended for baby mattresses is a density above 23 kg/m³. The Kotone and Suzu mattresses use high-resilience foam with a density of ≥23 kg/m³. The Mokuren does not use foam as its core — it uses pocket springs, where stability comes from the structure of the springs.

If you are comparing brands, ask for this figure. If they do not give it to you, that is information in itself.

Certifications: OEKO-TEX Standard 100 and EN 716

A baby's skin spends 14 to 16 hours a day in contact with this surface. Two certifications matter:

  • OEKO-TEX Standard 100 — certifies that the fabrics have been tested for substances harmful to the skin. All the fabrics in Dreamura baby mattresses carry this certification.
  • EN 716 — the European safety standard for cots, covering the stability of the frame, the spacing of the bars and its strength. The Nekasu cot complies with EN 716 and has a non-toxic finish, with paints and varnishes free from harmful substances.

There is no need to memorise the names of chemical compounds. It is enough to look for these two labels: one for the textile, the other for the frame.

The right size: no gaps

There must be no space between the mattress and the bars of the cot. The rule of thumb: if two fingers fit between the mattress and the frame, the mattress is too small. In figures, a gap above 3 cm is too much.

The usual sizes in Portugal:

  • 118×58 cm — the standard Portuguese slatted cot. This is the size of the Nekasu cot.
  • 120×60 cm — the most common European size, and the one you will find on most imported cots.
  • 140×70 cm — large cot or transition bed.
  • 190×90 cm — children's bed and Montessori beds.

The Kotone and the Suzu come in 118×58, 120×60 and 190×90. The Mokuren comes in 120×60 and 190×90. Always measure the inside of your cot before buying — the fit is a matter of safety, not comfort.

Hygiene: the protector is not an accessory

Babies spill, bring up milk and leak through the nappy. A baby mattress without protection absorbs all of that, and the core cannot be washed.

The outer fabric of our baby mattresses is not removable — as with most cot mattresses on the market. That is why I always recommend a waterproof, machine-washable mattress protector over the top. It is the piece that gets washed, and it is what makes the mattress last. The Tsuwano works well for a cot.

The mattresses are antibacterial and anti-dust-mite, but that does not replace a washable layer.

Dreamura baby mattresses

Three mattresses, for three different moments. All with medium firmness, OEKO-TEX Standard 100 certified fabrics, breathable fabric with temperature regulation, made in Portugal, a 100-night trial at home and a 3-year warranty.

Model Core Height Sizes Age Who it is for
Kotone (琴音, "the sound of the koto") High-resilience foam, ≥23 kg/m³ 8 cm 118×58 · 120×60 · 190×90 From 0 to 2-3 years The first bed. The most affordable, from €99.
Suzu (鈴, "little bell") High-resilience foam, ≥23 kg/m³ 11 cm 118×58 · 120×60 · 190×90 From 0 to 3 years 3 cm taller than the Kotone and more resistant to use. Our best seller for babies.
Mokuren (木蓮, "magnolia flower") Pocket springs 12 cm 120×60 · 190×90 From 0 to 5-6 years / Montessori Pocket springs, rare in a baby mattress. To buy once and carry through to the Montessori bed.

And if you are setting up the room from scratch, the Nekasu cot — sliding side, base adjustable to 3 heights, solid wood and MDF, non-toxic white finish, compliant with EN 716 — was designed for the 118×58 mattress to fit with no gaps.

Frequently asked questions

What is the minimum density recommended for a baby mattress?
Above 23 kg/m³. Below that, foam tends to give way with use and to lose the firmness that makes the mattress safe. The Kotone and the Suzu meet this figure.

Which certifications should I look for?
OEKO-TEX Standard 100 on the mattress fabrics, and EN 716 if you are buying the cot. The first guarantees the absence of harmful substances in the textile; the second covers the structural safety of the cot.

Springs or foam for a baby?
Both are safe as long as they are firm. High-resilience foam (Kotone, Suzu) is lighter and more affordable. Pocket springs (Mokuren) are silent, adapt point by point and last more years — a good choice if you want a single mattress from the cot to the Montessori bed.

What size do I need?
It depends on the cot: 118×58 for the Portuguese standard, 120×60 for most European cots, 140×70 for large cots and 190×90 for transition and Montessori beds. Measure the inside of your cot and confirm that no gap is left next to the bars.

Is the cover washable?
The outer fabric is not removable. That is why I always recommend a waterproof, machine-washable protector over the top — it is the layer that gets washed and the one that protects the mattress.

When should the baby mattress be replaced?
When the child moves to a larger bed, or before that if the mattress loses firmness or keeps a permanent mark. The Mokuren, in the 120×60 size, lasts up to 5-6 years.

Can I use a second-hand mattress?
I do not recommend it. A used mattress may have lost firmness and accumulated moisture and dust mites. For a baby, start with a new, firm mattress.

Can the mattress make the baby too warm?
It can, if the fabric and the core do not let air through. Overheating is one of the factors associated with unsafe sleep. Our baby mattresses use breathable fabric with temperature regulation, and the room should stay between 18 and 20 °C.

If you are hesitating between the Kotone, the Suzu and the Mokuren, I will call you and help you choose in 10 minutes: +351 21 150 95 04. You can also book through the Sleep Advisor page.

Note: this guide is informative and does not replace paediatric advice. If you have any doubt about your baby's safe sleep, speak to your paediatrician.

See also

See the Dreamura baby mattresses · See the whole baby collection

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