Royal Caribbean International, P&O Cruises and Disney Cruise Line – which all permit babies over six months to sail with them – will provide free cots in cabins, a range of equipment including changing mats and high chairs, and suitable food. Nappies and wipes can be bought on board (or pre-ordered on Royal Caribbean), which helps slim down your packing. When it comes to a cabin, children this age require more space than their size might suggest. Consider a state room with means to curtain off the cot so you don't have to sit in the dark in the evenings, and if your child naps in the afternoon, booking a balcony cabin is a no-brainer. Unlike almost every other line, Disney features bathtubs even in standard cabins.