Are swim diapers required for children three years of age and younger? Yes, swim diapers are required for children three years of age and younger. Swim diapers are available for purchase at the Water Park in the Surf Shop. Was this article helpful? Related articles Are cotton shirts allowed on the slides? Are rash guards allowed? What items can I take with me to the Water Park? When is the best time to visit LEGOLAND Water Park? Are towels available for rent or use in the Water Park?