Hi Emma,
Welcome to the Disney Parks Moms Panel! One of my favorite things about Walt Disney World is there are so many great attractions with no height requirement! If an attraction does have a height requirement, it will be posted along with a sign with the correct height so your children can check to see if they're tall enough.
If you want to do some research ahead of time, the
Walt Disney World web site is the place to go. If you go to the attraction page for each park, the attractions will have any height requirement listed. If for instance you go to the
Attractions page for the Magic Kingdom, you can find any of the possible height requirements, like
Big Thunder Mountain Railroad has a 40 inch height requirement. You can see if your kids will have to forgo any of the attractions on this visit, and find alternatives.
Please let me know if I can help you with any other questions.
Wishing you a magical vacation,
Amy H.