Hi Caitlin!
Thanks for stopping by the Disney Parks Moms Panel! We love to help with all types of trip planning questions!
No worries about bringing a bag with you into the theme parks. I often carry a small backpack type bag with sunscreen, extra water bottles, and any medicines we might need. I even throw in a couple of extra band-aids so that a rogue blister doesn't hinder our park touring. There are some
property rules for bag size: Bags and coolers, with or without wheels, cannot be larger than 24" long x 15" wide x 18" high. Of course, these rules can always change, so I would check back again closer to your travel dates if you're planning on bringing a bag close to that size.
When entering the parks with a bag, you will need to go through the bag check security line. Cast Members there will quickly scan through your bag to ensure there aren't any prohibited items. The bag check line generally moves very quickly but can have a small wait at peak times (like park opening), so be sure to plan a little extra travel time if you'd like to be in the parks at opening time.
Keep in mind too that you'll often need to carry your bag on to many of the attractions you'll experience. Usually, there is a place to tuck a bag away so you'll want to be sure not to exceed the bag sizes. If you do, your bag may not be able to be stored safely during the attraction.
If you'd like to bring a bag with you but not have to lug it around the park all day, each theme park location offers
lockers rentals. Lockers are usually located near the front entrance to each park. Availability is based on a first-come, first-served policy.
I hope you have a great time planning your upcoming Walt Disney World vacation! Be sure to let us know if we can help with any additional details.
Kathie