1. You can’t take a baby under six months on most cruises, and you have to wait until he’s 1-year-old for some destinations.
2. Swim diapers aren’t allowed in pools; look for ships with splash features if your child isn’t potty trained. Kids also need to be potty trained for many drop-off clubs.
3. Bathtubs aren’t standard in all cabins on any lines except Disney. Check the cabin layout before you book.
4. All major cruise lines offer portable cribs, but you must book them in advance.
5. Some cruise lines will allow you to preorder diapers and wipes; consider doing so if you are flying to the port and have to pay for checked luggage.
Source: Colleen McDaniel, editor of CruiseCritic.com.