Hi Michaela and thank you for visiting us again at planDisney!
A Western Caribbean cruise itinerary is lovely and it's great that you are planning ahead for your voyage this summer. August is definitely a warm time of year and it just makes the pools onboard or beaches at your ports of call all the more refreshing.
If you would like to pack a reusable water bottle with you on the ship, you are welcome to ask a Cast Member at a beverage station for cups of water and ice with which to fill it. You are allowed to take your reusable water bottles off the ship when you are in port to stay nice and hydrated.
Alternatively, you may purchase water bottles onboard or even bring your own disposable water bottles with you on the ship, as long as they are unopened and in your carry-on luggage only. Of course, I understand if you'd prefer a reusable water bottle, especially the type that can keep drinks cold for an extended period of time. I just want you to know that you have many options! I always love to recommend that guests
pack a swimsuit, sunscreen, and hat in their carry-on luggage as well to be able to cool off in the pool and enjoy the sunshine soon after boarding.
If you have any other questions about what items are allowed onboard the Disney Cruise Line, there is a handy reference list I'll link to
here. And if you have any other questions about anything at all, please visit us again. We'd love to help make your voyage as magical as possible.
Happy Planning!
Adrianna