Hi Macie! Welcome to planDisney! Thanks so much for stopping by to ask this great question.
The Happiest Place on Earth is the perfect place to
celebrate birthdays! I think it's equally magical to go when you have little ones! To enter a theme park, both a valid theme park admission and reservation for the same park on the same date are required for each Guest age 3 and older. You could bring your son to
Disneyland Park or
Disney California Adventure Park before he turns three for free. Once he turns three, even if it happens during your vacation, he would need a
Theme Park Ticket and
Theme Park Reservation for each day on and following his birthday. It's up to you if you decide to visit before his third birthday, and while he can still enter the theme parks for free.
There is a
Kids’ Special Ticket Offer where children ages 3 to 9 can visit for as low as $50 per child with a special 1-Day, 1-Park Ticket for a limited time. If the dates of your vacation align with the offer and park reservations are available, you might consider this offer so you could visit on and after his birthday. This offer is subject to restrictions and change or cancellation without notice. Sales may also be paused from time to time or terminated at any time, so you will want to decide as soon as possible if you are interested in the offer.
I hope this information helps with your planning. If you have more questions, please stop by planDisney again. We would love to help!
Wishing you magic,
Lisa