Yes, you are absolutely allowed to bring your own outside food and nonalcoholic beverages into Disney theme parks (Disneyland and Walt Disney World). This is a popular way for families to save money on expensive park dining. However, there are a few strict rules: your food cannot require heating, reheating, processing, or refrigeration (cast members will not heat up meals for you). Furthermore, you cannot bring glass containers (except for small jars of baby food) or loose/dry ice; you must use reusable ice packs or frozen water bottles to keep items cool. Your cooler or bag must also fit within the park's size restrictions (typically no larger than 24" x 15" x 18"). When you arrive at security, be prepared to tell the cast member you have food items so they can perform a quick check. Bringing snacks like granola bars, fruit, and sandwiches is encouraged, but leave the pungent-smelling foods or large rolling coolers at home to ensure a smooth entry.