Gunnar,
Thanks for asking your question to planDisney!
Yes, you can bring a bag into the theme parks at Walt Disney World, and no, it does not have to be a clear bag like at so many concert and sporting venues around the country. You can check
park rules for allowed items ahead of time, but you should be good with a bag of daily essentials.
When you come to a Disney theme park there will be a bag check where they will perform a quick inspection. It is a fast process, nothing that will significantly delay your arrival into the magic. Many of the rides have a space in your ride car to store a backpack or bag while you ride. That is not on every ride, but it is on most attractions where it might be needed.
BONUS TIP #1If you want to store your bag once you are in the park, there are
lockers available to rent. They are at the front of the park after passing through the turnstiles, and there are a few locker sizes available. They are keyless and typically will cost you $15 or less for the day. The
Magic Kingdom Park and
EPCOT even have a few larger lockers available that are up to 17" x 22" x 26" (43 cm x 55 cm x 66 cm). Prices can change, so check first online for current rates.
BONUS TIP #2If you want to bring in a cooler it must be 24" x 15" x 18" (61 cm x 38 cm x 46 cm) or smaller, and no loose ice or dry ice is allowed.
Write me back if you have any follow-up questions.
Have a Magical Vacation!
Doug