Ahoy, Christine!
Thanks for stopping by the Disney Parks Moms Panel with your question.
Guests of Disney Cruise Line are more than welcome to bring bottled water, sealed and in its original packaging,
onboard in their carry-on bags. I typically pack bottled water in a carry-on bag that has wheels and a handle, because a bag full of water bottles can be heavy! You'll have your carry-on bags with you from the time you enter the port terminal until your stateroom is ready in the afternoon, so keep that in mind when packing your bags.
Did you know Disney Cruise Line ships have a 24-hour self-service Beverage Station on the pool deck? Guests have access to a variety of Coca-Cola brand soft drinks, including Coca-Cola, Diet Coke, Sprite, Minute Maid Lemonade, Seagram's Ginger Ale and Fuze Iced Tea (offerings always subject to change). The drink stations have coffee and hot cocoa available as well. Cups are provided at the drink station, but I usually pack a travel mug or large acrylic drink cup with a lid to fill with my favorite soft drink. Feel free to bring a cup of your own, or pick up a new one at one of the onboard gift shops. (I'll admit I have more than a few Disney Cruise Line cups in my cabinet at home!)
I hope this helps with your preparations for an upcoming Disney Cruise Line vacation. Have a magical day! - Diane W.