Cot mattress buying guide

We’ll help you choose the perfect cot mattress for your baby’s cot.

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Quick facts about cot mattresses:

  • When selecting a cot mattress, the most important things to consider are whether the cot mattress meets important safety standards, is comfortable and durable.
  • While some cot mattresses are included when you purchase a cot, you might still want to purchase a better, separate mattress.
  • Prices range from around $50 up to $500 or more, depending on brand, model and material.

Types of cot mattresses

There are four main types of cot mattresses: foam, spring interior, natural fibre and hypoallergenic.

For those who are unsure which material is best for you, here are the pros and cons of each:

Foam: Usually made from polyurethane with a PVC cover and comes in a range of thicknesses. Opt for one that's on the heavier side for greater firmness and safety.
  • Cheap
  • Lightweight and easier to lift
  • Easy to keep clean
  • PVC cover could be too hot in summer
  • Less durable
Spring interior: Made from coil springs that are covered with a foam layer, as well as cotton and wipe-clean plastic.
  • Firmer
  • Could be more comfortable
  • Heavier and more durable
  • Will cost you more than foam
Natural fibre: Usually made from all-natural or organic ingredients, e.g. waterproof coconut fibres coated in latex on the inside and with a soft cotton cover
  • Free from chemicals that could be harmful to your baby's health and emit toxic gases, including flame retardants and vinyl
  • Durable
  • Costs more than foam or spring interior
  • Fewer options available
Hypoallergenic: Has a quilted top cover that can detach from the mattress body easily
  • For those with allergies or asthma in the family
  • Easy to keep clean
  • Could cost you more (an alternative would be buying a washable mattress cover with a regular mattress)

How to compare cot mattresses

When buying a cot mattress, consider the following key features:


If a mattress is too soft, your baby's breathing could get obstructed when they roll over into a face-first position. It also may not provide adequate spinal support for your growing child. Flat mattresses, which don't have cushioned, quilted or undulating surfaces, are more likely to be safe. Before purchasing a mattress, press down on the edges and centre of the mattress. A firm mattress should not mould to the shape of your hand and should spring back to its original shape quickly.


Pick a mattress with high density. If your mattress doesn’t list its density, particularly for foam models, check its weight instead. You can also test density by pressing one hand on each side of a mattress – a denser mattress won’t let you press your hands far in. For innerspring models, a firm mattress should have border rods for extra support, more innerspring layers, 135+ coils, a gauge of 15.5 or less and be made from thick insulator pads that contain coir fibres.

Waterproof cover

It’s recommended to get a waterproof, tight fitting, washable cover. This will protect your mattress from stains and nappy leakage. However, there’s a trade-off between waterproofness and how breathable the cover is. If you’re concerned about breathability, opt for a mattress with ventilation holes. Look out for models with double- or triple-laminated ticking that’s reinforced with nylon, which are more water- and tear-resistant.


Look out for mattresses with ventilation holes. This will ensure better airflow so your mattress doesn’t smell.

Cushioning layers

Look out for a mattress with layers made from cotton or foam. While those made from polyester tend to be cheaper, they’re also of lower quality.


You could consider a dual-firmness mattress, which has a firm side for babies and a softer side for toddlers. However, double-sided models will cost you more.

Additional feature

Eco-friendly materials

For those who have environmental concerns or are worried about how safe the chemicals used in standard mattresses are, there are all-natural, organic options available. However, these will probably cost you more. Compare the pros and cons of each material below:

  • Cloth covers. Instead of using vinyl, there are cloth covers available made from organic, unbleached, dye-free cotton or bamboo, which is renewable, antibacterial and antifungal. However, these materials won't prevent nappy leakages from soaking through your mattress, so it's recommended to get a waterproof mattress pad to complement your cloth cover.
  • Organic, waterproof mattress pads. Mattress pads that are completely waterproof cannot be all-natural or organic. They're often made with a cotton layer and a polyurethane layer. For those who want an all-natural product, you can consider wool pads, which are water-resistant but aren't 100% waterproof.< li>
  • Latex. Made from latex rubber, which is extracted from rubber trees. However, some babies may be allergic to latex.

How to check that the mattress fits

To keep your child safe, it's important to double-check cot fit, whether there are any gaps between the mattress and cot sides and the thickness of the mattress.

  • Cot fit. The cot mattress should fit snugly into your cot and satisfy the cot manufacturer's recommended dimensions, so double-check your cot's dimensions first before purchasing a separate cot mattress. When the cot mattress fit is too tight, parts of the mattress could curl up, allowing your child to potentially climb out of his or her cot. For dropside models, a tight mattress fit could also impede the drop sides from moving smoothly.
  • Gaps. Check there aren't gaps at the sides which are larger than 25mm (about 2 fingers) between the mattress edge and cot side, as this could be an entrapment or suffocation risk.< li>
  • Thickness. Ensure your chosen cot mattress has a minimum distance between the top of the mattress and the lowest side of the cot of 50cm when the cot is in its lowest position and at least 30cm in its upper position.
Is it safe to use a second-hand mattress?

An old, worn mattress is more likely to have breathability issues with greater suffocation risk, is less hygienic and less durable. Also, if a used mattress has foam or padding exposed, it could be more likely to attract bacteria and mould growth.

Tips for safe sleeping

  1. If you're purchasing a vacuum-packed mattress, ensure it's inflated to its full size before use, or else it may not be safe for your baby.
  2. Avoid wrapping your mattress in plastic or any unbreathable material.
  3. Soft toys and bumpers are a suffocation risk and should not be placed in the cot.
  4. Place your baby on their back with feet at the cot base.
  5. Avoid using doonas, pillows, wool or thick blankets in the cot.
  6. Blankets should be tucked in tightly and shouldn't cover your baby's face. Alternatively, use a safe sleeping bag.

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