Yes, Disney Parks have a specific policy regarding backpacks and bags to ensure guest safety and smooth operations. All bags, including backpacks and coolers, must not exceed 24 inches long x 15 inches wide x 18 inches high (61 cm x 38 cm x 46 cm). Every bag is subject to security screening, which may involve X-ray machines or manual inspections. Prohibited items that cannot be carried in your backpack include glass containers (except small baby food jars), alcoholic beverages, selfie sticks, and loose ice (reusable ice packs are recommended instead). It is also important to note that while backpacks are allowed in the parks, they must be stored in lockers or placed in designated floor compartments during certain high-intensity rides to prevent them from becoming a hazard.