Is your toddler younger than two years? If he/she is older than two years, than your child can participate in the youth program. (Counselors will change diapers.) If your little one is younger than two years, Carnival does have limited hours for group babysitting that babies and toddlers can come to. It's usually in the morning on port days and late at night too.
Just make sure you realize that traveling with a toddler may not be a relaxing experience, but it can be a fun one! My 23 month old has been on four cruises and he loves walking around all the public rooms, checking out the glass elevators, etc. Make sure you bring swim diapers for the splash pool too. You may want to read the article I wrote on this site, "Bringing the Baby" on tips for cruising with babies and toddlers.
Let me know if you have any add'l q's.
Luisa Frey Gaynor
Family Cruise Editor