13 best cot mattresses in 2024 to help little ones (and parents) sleep soundly

Whether you’re in the throes of nesting and want everything in the nursery ship shape before baby’s arrival, or you’re approaching the half-year mark and looking to make the big move from parent’s bedroom to your bedside companion sleeping in their own space, you’ll need to consider purchasing a cot mattress.

Typically, cot mattresses come in two sizes: for a standard crib, the measurements are 120cm x 60cm and 140cm x 70cm for a cot bed. As the name suggests, a cot bed is a slightly larger cot with removable sides, which transforms into a toddler bed lasting them until around four years old, so usually offers parents a little more bang for their buck.

With any form of bedding, comfort is key, but when it comes to creating a sleeping environment for babies, safety must be at the forefront. Children’s charity The Lullaby Trust, which spearheads safe sleep for babies, strongly advises that your little one’s mattress is flat and there are no gaps (or at least, no more than a 1cm gap) around the mattress.

While adults may prefer a soft mattress, babies need a firm and flat surface because this helps them move around easily, and ensures they don’t overheat as there’s plenty of airflow. According to The Lullaby Trust, the mattress should be firm enough that when your baby is placed on it, their head doesn’t sink in more than a few millimetres. It’s also recommended that a mattress is waterproof or has a fitted waterproof cover to help prevent bacteria from building up inside the mattress, thus lessening the risk of infection.

How we tested the best cot mattresses

Our Coxley cot bed from Mamas & Papas (£599, Mamasandpapas.com) became the home to a variety of mattresses over the course of a month. Our young tester obliged to naps and overnight sleeping (most of the time), while we considered each mattress’s credentials; firmness, fit to the cot, breathability and practicality, such as care, maintenance and price.

All mattresses tested complied with BS 1877-10:2011+A1:2012 (the standard that specifies the materials that can be used for children’s mattresses) and consisted of either foam fibre, which is often the cheaper option, pocket springs designed to be firm, comfortable and supportive or natural fibres, like coconut coir. The mattresses we tested are all available in both cot and cot bed sizes.

The best cot mattresses for 2024 are: