Yes, you are absolutely allowed to bring your own water bottle into Disneyland and Disney California Adventure in 2026, and it is highly encouraged for staying hydrated in the California sun. The official policy is straightforward: guests may bring outside non-alcoholic beverages provided they are not in glass containers, which are strictly prohibited for safety reasons. You can bring plastic, stainless steel (like a Yeti or Hydro Flask), or silicone bottles. Security will check your bag upon entry, and you should inform them if you have any liquids. Once inside, you can take advantage of numerous "Bottle Filling Stations" located throughout the parks, such as in Tomorrowland or Star Wars: Galaxy's Edge, or simply ask for a free cup of ice water at any quick-service dining location to refill your bottle. This is a significant money-saver, as bottled water inside the parks can cost over $5.00. Just ensure your bottle is not made of glass and that you do not bring in loose ice (reusable ice packs are permitted), and you will have no trouble at the security checkpoints.