Currently there is no flight to Perhentian Island. The only way to go there is by the sea especially a boat services from Kuala Besut. 

Please make sure you are equipped with safety jacket on the boat. At sudden time the current from South Chinese Sea is strong. It is just a safety measures for you.

From Kuala Lumpur International Aiport, available domestic flights are provided byMalaysia Airline System and AirAsia's low cost flight. You can book the ticket online. If you are really on a tight budget, better get the AirAsia flight.