Tullamarine airport
The main airport is Tullamarine and is 22km northwest of the City of Melbourne. The International and Domestic terminals are connected with the exception of Tiger Airways which has a small crowded terminal a short distance from the main domestic terminal. The terminals have plenty of facilities.
Skybus
Public Bus
A cheaper alternative is to use the public bus and for that you will need to buy a Metcard. The Airport is in Zone 2 and the city centre is in Zone 1. Either of these tickets will allow you to transfer to other buses, trams and trains as many times as you wish within its validity. Two hours should be quite sufficient to get to your destination, but if you have spare time for the rest of the day, you might prefer the all-day ticket.
Taxi
There are plenty of taxis and might work out cheaper than Skybus if you are a family.
Avalon Airport
A few domestic flights operate to Avalon Airport south of the city towards Geelong. Buses operate to Melbourne and Geelong. Avalon is very convenient if you are going to Geelong or direct by car hire to the Ocean road.