Definitely depends on the kid. We took our daughter on an Alaskan cruise for her 2nd birthday and we've now done two Caribbean sailings as well - one on Wonder, the other one Harmony. She's 3 and had a blast - like you said, she enjoyed the splash area, shows, frozen drinks, etc. That said, I also know plenty of kids who would be miserable and make their parents miserable as well by throwing tantrums and generally being a Royal pain.