Disneyland (and Walt Disney World) officially starts charging for children's admission once they reach their third birthday. Children under the age of 3 (ages 0 to 2) are considered "Guests of Mickey" and receive free entry to the theme parks; they do not require a ticket or a park reservation. Once a child turns 3, they require a Child’s Ticket, which applies to ages 3 through 9. This ticket is slightly discounted compared to an Adult Ticket. Once a child reaches age 10, they are classified as an "Adult" for ticketing purposes and must pay the full gate price. It is important to note that if your child turns 3 during your trip, Disney policy generally honors the age they were on the day of check-in or the first day of the ticket usage. You do not typically need to show a birth certificate at the gate, but if your 2-year-old looks like a 5-year-old, it is a good idea to have a digital copy of their ID on your phone just in case a Cast Member asks for verification.