Yes, hydration backpacks (commonly referred to by the brand name CamelBak) are fully allowed at all Walt Disney World and Disneyland theme parks in 2026. They are an excellent way to stay hydrated in the Florida and California heat. However, there are a few security rules to follow: the backpack must not exceed the standard bag dimensions of 24" long x 15" wide x 18" high, and it must be searched at the security checkpoint. Security cast members will likely ask you to open all pockets, and if the bladder is full of water, they may perform a quick "manual" check. One critical rule is that you cannot have loose ice inside the bladder or the bag; you must use reusable ice packs or fill it with ice after you clear security at one of the many "Quick Service" water stations. These backpacks are particularly useful because they allow you to sip water while waiting in long outdoor queues, and they usually have enough extra pocket space to hold a poncho and a phone charger, making them the "utility player" of Disney park gear.