Greetings, Meridith!
Welcome to the Disney Parks Moms Panel. Thanks so much for your wonderful question! I'm happy to let you know that you are more than welcome to bring outside food and beverages into the Disneyland Resort theme parks as long as they follow the official
Park Rules. This basically means no alcohol, no glass containers, and no large coolers.
I often like to bring small packaged snacks and bottled water. These are a lifesaver for my kiddo when we are waiting in line for an attraction. I think fruit, jerky, granola bars, and apple sauce pouches make great snacks that aren't messy. I also like to refill my water bottle throughout the day with the complimentary ice water cups at Quick Service restaurants in the parks. Staying hydrated is key when walking a lot in the hot California sun.
Sometimes I like to keep my snacks or extra layers of clothing in a convenient
locker rental in either park. These are great, because you only pay one low price and can access your locker as many times as you wish throughout the day. They also make a great place to store purchases I have made.
I hope this helps, and please return if you have any other questions about planning your magical vacation. Have a Zip-a-Dee-Doo-Dah day!
-Jennifer