Allyson,
Thanks for asking your question to planDisney!
You definitely can bring your cooler into the parks, since it falls inside the guideline of 24" x 15" x 18" (61 cm x 38 cm x 46 cm). If you check the
Walt Disney World Resort Property Rules page, you will see that you appear to be good to go!
BONUS TIP #1
Make sure you do not use loose or dry ice. That is prohibited. You can, however, use ice packs.
BONUS TIP #2In
EPCOT and the
Magic Kingdom Park there are oversized
lockers you can rent that are 17" x 22" x 26" (43 cm x 55 cm x 66 cm). Unfortunately they don't have lockers quite that big in
Disney's Hollywood Studios, and
Disney's Animal Kingdom Theme Park, but for at least one day you likely could store the cooler. Check first before renting to ensure that the dimensions of the locker and your cooler align correctly, but this could be a great way to free yourself of the cooler until it is needed!
Write me back if you have any follow-up questions.
Have a Magical Vacation!
Doug