Yes waterkingdom offers “celebrte you birthday with us” that means there will be no charge on ticket of waterkingdom just you have to show your valid id proof of your birth date and these offer is mention on its official website that is https://waterkingdom.in I visited on 17th april and it was tuesday so no rush on any ride and no extra cost of any ride inside waterkingdom. rides are really awsome and scary rides you have to pay for your meal because you cant take your own food inside a waterpark price of food is fare enough.