Once you leave Australia permanently, you will cease to be a resident for tax purposes on the date of your departure. Before that date, you will be liable for tax on your worldwide income. After that date, you will be liable only for your Australian-sourced income. The situation is reversed for those returning to Australia permanently.
Whether arriving or departing, you should answer “Yes” to the question “Are you a resident?” on your tax return.
You will be taxed at the resident tax rates, but because you were a nonresident for part of the year, you will be taxed at a lower tax-free threshold than normal residents. You will be taxed at a pro-rata tax-free threshold for the number of months you were an Australian resident.
You will also be responsible for the Medicare levy only for the time you were a resident. You can claim an exemption for the number of days you were out of the country.