Ahoy, Amelia!
Thanks for stopping by the Moms Panel with your question. I'm happy to help!
Disney Cruise Line wants to make sure that each and every guest that sails with them is comfortable, safe, and treated like a VIP. You'll find that most of your needs on the ship have been taken care of, even before you have them!
No need to worry about wasting valuable space in your suitcase with life jackets. As a courtesy to guests, complimentary pool vests are available on the pool decks aboard all ships in the fleet. Life jackets are also available on Disney's private island,
Castaway Cay. I've always found them to be plentiful, and have never worried about them not having enough to accommodate the guests. If your child has a particular style he/she is most comfortable swimming in, or just needs "floaties", then you might want to consider bringing your own.
I hope this helps with your planning and packing! It won't be long until you'll be sailing away with Captain Mickey!
Have a magical day! - Diane W.