What is there for kids to drink on a Royal Caribbean cruise?
There are lots of free options for your kids.
At breakfast you will find Milk, Chocolate milk, Apple Juice, Orange Juice and of course water.
At Lunch and dinner there is water, lemonade, iced tea and usually a flavored water that can very from day to day. Milk is available upon request in the buffet and you should have no problem getting it in the Main Dining Room.
I don't think your kids drink it, but you can also get coffee and hot tea if you wish as well.
Hope this helps!
You also have the option to either purchase a soda package, or purchase individual sodas if that is of interest to you. My kids almost always drink the free drinks with an occasional soda thrown in as a treat.