We just got back from Disney Cruise Line and they have two pool options for kids -- the Mickey Mouse splash pool that my almost five year old loved as well as a bigger, deep pool for kids. Both get crowded, but most cruise line pools do get crowded on sea days. My son was tall enough for the slide that is by the Mickey pool and loved it.
Luisa Frey Gaynor
Family Cruise Editor
P.S. All Disney cruises also call at Castaway Cay, its private island, which is fabulous for kids for swimming. Clear, calm water with a jungle gym apparatus in the water for kids too....