Owing to its unique geography, Sydney has a menagerie of public transportation options, including buses, trains, light rail, and ferries. If you're near the CBD or happen to live close to a train station or ferry stop then public transit is a great option. In some areas, particularly Central Sydney and its surrounding suburbs, you won't need a car. But the further out you get the more likely it is you will need one.
All public transit can be accessed with the Opal card. This is a smart card, similar to a credit card, that you tap on a sensor when you enter and exit transportation. There are four versions:
Besides the four categories above, fares are also based on distance traveled.
HAVING A CAR IN AUSTRALIA
We all get attached to our cars, but you should think twice before you bring it with you to Sydney. Importing a used car into Australia will nail you with a $12,000 duty imposed by customs. (Note that this duty will go away starting in 2018.)
The flip side of this argument, if you will really need a car, is that cars in Australia are incredibly expensive. Luxury cars can be two or three times the cost of vehicles elsewhere. A 2011 report found that a Lexus LS460 that cost USD $66,000 in the United States would cost AUD $191,000 in Australia – and that was a time when the two currencies were at parity. Even with the fall in the Australian dollar, that's still a significant premium.
And even used cars – very used, undesirable cars – can be expensive. A clunker that would be a few thousand in the U.S. can be $7,000-9,000 in Australia. You'll also need to get handy driving on the the left-hand side of the road if you come from the majority of countries that drive on the right.
Still, having a car in Sydney does offer the freedom to shoot down the coast to places like Hyams Beach, west to the Blue Mountains, north to the Hunter Valley wine country, or any of the other amazing places close to the city.
HELPFUL TRANSPORTATION WEBSITES
Trip Planner - The official Sydney Transport site has a great planner that lets you select (or deselect) different modes of transport and shows you timetables.
Car buying in Sydney. What to know and what questions to ask.