Cot Mattress Buying Guide: Sizes and Materials Compared
By Cuddleco | Published: 2026-10-22
Category: Buying Guides
Find the right cot mattress size and material for your baby's age and sleep needs. Compare pocket sprung, foam, and coir options with clear decision rules.
Quick answer
Choose a cot mattress that fits your cot bed size with a snug gap under 3cm. For long-term use, a pocket sprung cot mattress offers better support as your baby grows; for a lightweight option, a foam cot bed mattress works well.
Why cot mattress size matters more than you think
A cot mattress that is too small leaves a dangerous gap where your baby could trap an arm or leg. Too large and it won't fit the cot frame at all. The standard UK cot mattress size is 140 x 70cm, but always measure your cot bed before buying. Moses basket mattresses are smaller, typically around 66 x 28cm.
Material trade-offs: pocket sprung vs foam vs coir
Pocket sprung mattresses have individual springs that contour to your baby's shape and offer consistent support as they grow. They tend to be heavier and more expensive. Foam mattresses are lightweight and affordable, but may not last as long. Coir mattresses are firm and breathable, often combined with pocket springs for extra comfort.
Decision rules for choosing your cot mattress
- If your baby is newborn to 6 months: Choose a firm mattress with a breathable cover. A hypoallergenic cot mattress with bamboo fabric reduces allergens and helps maintain a clean sleep surface.
- If your baby is over 6 months or you want longevity: A pocket sprung cot mattress offers better support as your baby grows heavier and more active. Look for a mattress with two sides to transition from firm to slightly softer.
- If your baby has allergies or sensitive skin: Opt for a cot bed mattress with anti-allergy protection like Purotex® and natural fibres such as TENCEL™ or bamboo. Avoid pure foam which can trap dust mites. Check if the mattress cover is removable and washable for ongoing allergy control.
- If you need a mattress for a Moses basket: Choose a Moses basket mattress in the correct size (e.g., 66 x 28cm). These are typically foam-based for lightweight portability, but still need to be firm and breathable.
Product facts at a glance
- Signature Hypo-Allergenic Bamboo Pocket Sprung Cot Mattress 120 x 60cm: The Signature mattress features pocket springs that gently contour and respond to your baby's sleep position, with a hypoallergenic bamboo fabric side. This mattress grows with your baby from newborn to toddler, offering two sides for different stages.
Signature Hypo-Allergenic Bamboo Pocket Sprung Cot Mattress 120 x 60cm - Mother&Baby Pure Gold Anti-Allergy Coir Pocket Sprung Cot bed Mattress 140 x 70cm: The Mother&Baby Pure Gold mattress combines TENCEL™ fibres and Purotex® anti-allergy protection in a coir and pocket sprung construction. Ideal for allergy-prone babies, this mattress provides a fresher sleep environment with natural firmness.
Mother&Baby Pure Gold Anti-Allergy Coir Pocket Sprung Cot bed Mattress 140 x 70cm
Which mattress fits your situation?
Best for
- Parents who want a long-lasting mattress that adapts as their baby grows
- Babies with allergies or sensitive skin who need hypoallergenic materials
Not for
- Budget-conscious buyers who need the lowest upfront cost (foam options are cheaper)
- Parents who prefer a lightweight mattress for frequent moving between rooms
