Yes, water backpacks (like CamelBaks) are absolutely allowed in all Walt Disney World theme parks in 2026. They are an essential tool for staying hydrated in the intense Florida humidity. However, they must comply with the general bag policy: they cannot exceed 24" long x 15" wide x 18" high. At the security checkpoint, you must ensure the bladder is completely empty of liquids; security needs to verify the contents before entry. Once inside, you can refill your reservoir for free at the various "Hydration Stations" or at any Quick Service location by asking for a cup of ice water. In 2026, many frequent visitors use these to avoid the $5+ cost of bottled water. Just remember that loose ice is not permitted in bags—use reusable ice packs instead—and avoid taking them into Animal Kingdom if they have long, dangling "straw" tubes that could pose a hazard to wildlife.