Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Surabaya to Gold Coast as you normally would.
Located just 15.0 km from the city centre, Surabaya Juanda (SUB) is the airport most travellers will use when flying to Gold Coast from Surabaya.
This is defined as Surabaya Juanda Airport (SUB) and Coolangatta Gold Coast Airport (OOL). Codes like Coolangatta Gold Coast Airport are often used to just call airports uniquely.