You land in Australia, you start a job, and you assume the tax you pay here is tax on what you earn here. For many new arrivals, that assumption is wrong — and the gap between it and reality is where the surprise bills come from. Becoming an Australian resident for tax purposes flips a switch that reaches your overseas salary, your foreign rental, your investments back home and even the way your assets are valued. Here's the mechanic behind the shock, explained without the jargon.
The switch: from local income to worldwide income
This is the single biggest thing migrants miss. A foreign resident is taxed by Australia only on Australian-sourced income. But once you become an Australian resident for tax purposes, the ATO taxes you on your worldwide income — wages, business profits, interest, dividends, foreign pensions and capital gains, wherever in the world they arise. You must declare all of it on your Australian return.
So the overseas rental property you kept, the dividend stream from your home-country shares, the freelance work you still do for a client back home — all of it can become assessable in Australia from the day you become a resident. Foreign tax already paid is usually credited so you're not taxed twice, but the income still has to be reported, and Australia's rates may be higher than what you were used to.
Three residency tests decide it — and any one is enough
The ATO doesn't ask whether you feel Australian. It applies a set of tests, and you only need to satisfy one to be a resident for tax purposes:
- The resides test. The primary test — do you actually live here, judged on things like your physical presence, family, employment and the location of your assets and life.
- The domicile test. If your permanent home (domicile) is in Australia, you're a resident unless the ATO is satisfied your usual place of abode is overseas.
- The 183-day test. If you're physically present in Australia for 183 days or more in an income year, you're presumed a resident — unless your usual place of abode is overseas and you don't intend to take up residence.
(A fourth, the Commonwealth superannuation test, applies mainly to certain government employees.) Because the tests are broad, plenty of people become tax residents earlier than they realise.
The CGT reset most people have never heard of
Here's a rule that cuts both ways. When you become an Australian resident, you are taken to have acquired your assets at their market value on the day you became a resident — the ATO calls this "deemed acquisition." It applies to your CGT assets other than taxable Australian property (such as Australian real estate).
The good news: it generally means Australia only taxes the growth after you arrive, not gains that built up while you lived overseas. The catch: you need to know and document the market value of everything on your arrival date — your foreign shares, crypto, managed funds and the like. Miss that, and years later, when you sell, you can end up unable to prove the higher starting cost base, and paying CGT on growth that was never really Australian.
The rates that bite before you're a resident
If you arrive part-way through a year, or work here before you're treated as a resident, the rates are unkind. Foreign residents get no tax-free threshold — the $18,200 that residents earn tax-free doesn't apply. Instead, tax starts from the very first dollar.
Working holiday makers (visa subclasses 417 and 462) are taxed under their own schedule: 15% on the first $45,000, then foreign resident rates above that, again with no tax-free threshold. Backpackers who expected the same $18,200 tax-free start as locals are often the most surprised of all.
And don't forget the Medicare levy
Once you're a tax resident with access to Medicare, you generally also pay the 2% Medicare levy on top of your income tax — a cost foreign residents and most working holiday makers don't carry. For a new resident on a decent salary, that's a line on the bill that wasn't there before.
What to do before you arrive
None of this is a reason not to move — but a little preparation saves a lot later:
- Work out your residency date. It drives everything else, and it's not always the day you land.
- Record the market value of your overseas assets on that date — shares, crypto, funds, property abroad. That snapshot is your future cost base.
- Map your foreign income — rent, dividends, pensions — and check what's taxable here and what foreign-tax credits you can claim.
- Get advice if it's not simple. Cross-border tax is one area where a registered tax agent usually pays for itself.
The theme is consistent: Australia's tax system reaches further than newcomers expect, and the costliest mistakes are the ones made before anyone thought tax was even relevant.