We took our daughter on the cruise when she was two. She turned 2 on the ship. Last year, we had both our daughter (almost 4 at the time) and our son who turned 1 on the ship. As toddlers, they spent time in the nursery (which is great by the way), in the splash area, lot's of time walking around the ship, seeing characters, etc. Non-potty trained kids can not be in the pools. There is a splash area for non-potty trained kids, but they still have to wear a swim diaper. Our son loved it last time.
That is great to know!! Thanks for the information! I was wondering about the nursery so I am glad to hear it is great!