Disney parks often offer stroller rentals, but specific requirements may vary from park to park. Under normal circumstances, renting a stroller may require some identification, such as a passport, ID card or driver’s license, etc., to confirm the identity of the renter. Since your child is four years old, you can usually rent a stroller if his height does not exceed the specified rental standards. It is recommended that you learn the detailed rental conditions and procedures through official channels or the park’s customer service before going to Disneyland so that you can rent a stroller smoothly. At the same time, it is indeed troublesome to bring your own stroller to Japan. Renting a stroller from the park may be a more convenient option.