If you are booking a JetStar flight you can add this at the time of booking.
If you have already made your booking and wish to add this after, go on to Jetstar website www.jetstar.com/au and click on Manage booking
If you have booked on any other carrier give our team a call on 1800 719 668 or 02 7254 6361 and they will advice if they can book this for you.
Mix & Match fees apply for our team to do this.
In most cases if you can add this before you check in it will be cheaper than at the airport.
Some airlines do not allow this to be added and any extra baggage will need to be added and paid for at check in at the airport.