Your licence
As a temporary visa holder you can drive on your current overseas licence in every state and territory, for the classes of vehicle it covers, as long as it is valid and in English; if it is not in English, carry an official translation or an International Driving Permit ALONGSIDE the original (an IDP alone is not a licence). The fine print varies slightly by state, mostly around what happens if you become a resident or stay put long-term, so if you settle somewhere for many months, check that state's road authority (Service NSW, VicRoads, TMR in QLD, DoT WA and friends) rather than the hostel consensus. Carry the physical licence whenever you drive; digital copies do not always satisfy a roadside check. Two practical notes: your overseas licence class matters (a car licence does not cover that 4.5-tonne truck the farm wants moved), and camera fines follow the vehicle's registered owner, so if you borrow a mate's van, square up your fines like an adult, because they will chase the rego holder, and friendships have died over less.
The non-negotiables
Left side of the road, seatbelts for every occupant, and a 0.05 blood-alcohol limit, which is lower than many backpackers are used to and enforced by random breath testing at roadblocks, constantly, everywhere, at all hours. Drug driving tests are random and roadside too, and yesterday's session can still test positive today. Phones: touching one while driving costs a heavy fine and demerit points in every state, enforced by AI cameras that photograph through your windscreen, and the fine amounts climb every year (check the state road authority if you want to be depressed). Speed limits are enforced to within a few km/h by fixed, mobile and average-speed cameras; this is not a suggestion culture, and the 'tourist warning' you are hoping for is not a thing. School zones (usually 40km/h at set times) are the most heavily enforced metres of road in the country. None of this is anti-backpacker; Australians get exactly the same treatment, which is why they all drive like the cameras are real. They are.
Roos, roads and dusk
Kangaroos feed at dawn and dusk and bolt TOWARDS headlights, and hitting a big red at 100km/h writes off a van and sometimes its occupants. The rule every local follows: do not drive in the hour around sunrise and sunset outside towns, and if you must, slow right down and scan the verges. If a roo jumps out, brake hard in a straight line; swerving into a tree or the oncoming lane kills people, whereas roos usually do not. One more roo rule nobody enjoys learning: if you do hit one, stop when safe and check the pouch if you can bear to, and call the local wildlife rescue (WIRES in NSW, similar groups in every state); an injured roo on the road is also a hazard to the next car. Wombats are worse than roos (solid muscle at bumper height), cattle and camels at night are worse again, and in station country the 'unfenced road' signs and cattle grids mean exactly what they say. Plan country legs for full daylight and the whole problem mostly disappears.
Road trains and outback etiquette
Road trains run up to 53.5 metres, which is a truck the length of an Olympic pool with three trailers of momentum. Overtaking one needs about a kilometre of clear straight road, so do not attempt it on a whim, and when one approaches on a single-lane sealed strip, get right off the bitumen onto the shoulder and slow down, because they cannot and will not. Give them space at roadhouses, never pull out in front of one (they take forever to stop), and expect the wind blast when passing. The etiquette layer: wave to oncoming drivers on remote roads (one finger lifted off the wheel is the full formal version), stop for anyone broken down out there because the next car might be hours away, and if you carry a UHF radio, channel 40 is the truckies' channel and worth monitoring on the big highways. Breakdowns: STAY WITH THE VEHICLE, always. It is shade, it is water storage, it is visible from the air, and it is what searchers find. People who walk for help in the outback die within kilometres of a car that would have saved them; that is not folklore, it is a pattern the police will recite to you.
Floodwater, fuel gaps and planning
The flood rule is absolute and Australians drill it like a catechism: if it's flooded, forget it. Never drive into water over a road, however shallow it looks, because floodways hide washed-out road surfaces, the depth markers are there for a reason, and most flood deaths in Australia are people in vehicles who thought they would make it. Turning around costs minutes; the alternative costs everything, and some states fine drivers who enter closed flooded roads on top of the rescue bill. After rain, check official road-condition sites before any outback dirt road: they close formally, driving a closed road can void insurance and carries recovery costs in the thousands, and the mud out there eats 2WD vans whole. Fuel: outside the east coast, stops can be 150-300km apart (the Nullarbor, the Stuart Highway and inland WA are the classics), so never pass a roadhouse below half a tank, expect remote fuel to cost dramatically more than city fuel, and carry water always, 10L+ per person, because the fuel plan and the survival plan are the same plan.
Rego, roadworthies and the interstate trap
Registration (rego) belongs to a state, and the vehicle keeps that state's rego wherever it physically is, which creates the classic backpacker trap: buying a van in Perth that wears NSW or QLD plates. Transfers must follow the rules of the rego's HOME state, and the eastern states require inspections and processes that are somewhere between painful and impossible to complete from across the country, so that bargain van can leave you unable to properly transfer ownership at all, driving on someone else's name, or forced to re-register it locally with a full inspection the van may not pass. The clean version of the rules: NSW, VIC and QLD require a roadworthy or safety certificate to transfer; WA and SA transfer without one (which is why half the backpacker fleet wears WA plates); transfers generally must be lodged within about 14 days with stamp duty on the price; and rego renewal usually requires an address in that state. So before money changes hands, ask one question: can I actually transfer THIS rego, in THIS state, this week? If the answer involves the words 'she'll be right', walk. Full detail in the Buying a Van guide, and check the actual road authority site for the state on the plates, not the seller's summary.
Paperwork, penalties and the kit
Rego, CTP insurance and (in some states) periodic inspections must all be current, and police cars read every plate automatically as they drive, so an expired rego gets found, not overlooked; driving unregistered also voids the injury insurance bundled with rego, which turns a fine into a catastrophe if anything happens. Unpaid tolls in NSW, QLD and VIC snowball from small change into three-figure fines per trip, so set up a toll tag or pass account the day you buy a vehicle if you will be near a city. Demerit points follow you between states; the 'different state, fresh start' theory is a myth told in hostels by people who later found out. Finally, carry the bush basics even on sealed highways: a real spare tyre you have actually checked, a jack that works with a board to stand it on, jumper leads or a jump pack, engine oil and coolant top-ups, a tyre pressure gauge and plug kit with a 12V compressor, basic tools, gaffer tape, a torch, and far more water than seems reasonable. Roadside assistance from the state auto clubs covers members Australia-wide through reciprocal arrangements and is the cheapest peace of mind on the market; out past the black stump, a commercial tow can cost more than the van did.