Most Cruise lines will allow infants to travel from 6 months old boy on certain voyages that cross the Atlantic and many of the Exotic cruises this increases to 12 months. Disney Cruise lines will allow babies on board from 12 weeks, considered one of the best at catering for babies and little people. However a Disney cruise may not be to your taste and if you prefer a more mainstream Cruise line. Each is very different in terms of what they offer especially with babysitting etc. Most will not offer any clubs or minding services until the child is 2 years old. Royal Caribbean offer play groups for babies of 6-18 months and Cunard have Nannies on board that will take care of your baby from 12 months old.