For the vast majority of guests in 2026, a birth certificate is not required for entry into Walt Disney World or Disneyland. Disney operates on an "honor system" for children under the age of three, who are considered "Guests of Mickey" and do not require a ticket. Cast Members at the gate rarely ask for proof of age unless a child appears significantly older than three. However, if you are traveling internationally, your child will need a passport. For domestic travelers, while not mandatory for park entry, having a digital copy of a birth certificate on your phone is a good "just in case" measure if your child is exceptionally tall for their age. The only time a birth certificate is strictly necessary is for specific Florida Resident ticket verification if the adult lacks a state ID, or for certain youth sports competitions held at the ESPN Wide World of Sports Complex where age verification is a formal requirement for the tournament.