The best mattress for a Moses basket is a firm, flat mattress specifically designed for Moses basket dimensions ensuring no gaps around edges. It should be made from breathable materials such as high-density foam, natural fibres like coconut coir or wool, or pocket springs allowing air circulation and temperature regulation. Essential features include waterproof or wipeable covers protecting from leaks whilst maintaining breathability, hypoallergenic properties suitable for sensitive baby skin, lightweight construction for easy removal and cleaning, and compliance with British safety standards. The mattress must be firm enough to support baby's developing spine and reduce SIDS risk - if you can make a lasting handprint impression, it's too soft. Never use soft, pillow-top, or memory foam mattresses in Moses baskets.

A Moses basket mattress fits properly when it sits snugly inside the basket with no gaps larger than 2cm (less than two fingers width) around any edge, lies completely flat without bending or curving at the edges, doesn't move or shift when you press down on the corners, and matches the basket's base shape (oval, rectangular, or curved) perfectly. To ensure proper fit, measure your Moses basket's internal dimensions (length, width, and depth) before purchasing, check the mattress specifications match your basket's size exactly, and test the fit by placing the mattress in the basket and checking for gaps. Gaps create dangerous entrapment hazards where baby's head could become wedged. If there are any gaps, the mattress is the wrong size and must not be used.

Most Moses basket mattresses feature removable, washable covers that zip off for machine washing at 30-40°C, making them easy to keep clean and hygienic. The mattress core itself (foam or fibre) should not be submerged in water but can be spot-cleaned with a damp cloth and mild soap, then air-dried completely in a well-ventilated area away from direct heat. For daily maintenance, wipe the waterproof cover with a damp cloth after accidents, air the mattress regularly by standing it upright, use waterproof mattress protectors for additional protection, and wash covers weekly or immediately after leaks. Always ensure the mattress is completely dry before use to prevent mould growth. Replace mattresses showing signs of wear, damage, sagging, or mould as these compromise safety and hygiene.