Your TFN is not gone. It is permanent, it was issued once, and it is almost certainly already written on something you still have: a payslip, a super fund statement, a notice of assessment, or the original ATO letter.
Where is it already written down?
Four places cover nearly everyone, and searching all of them takes less time than any process involving a phone call or an identity check. Your TFN was written down more often than you remember, usually by an employer or a super fund rather than by you.
- Payslips and income statements from any Australian employer, many of which display it
- Superannuation fund statements and welcome letters, if you gave the fund your number
- Any Australian tax return you have lodged, and the notice of assessment that followed it
- The original letter the ATO posted when the number was issued
The fastest single move is searching your email for the phrase tax file number. Most people who believe they have lost it find it within a few minutes, usually in an onboarding email or in fund correspondence they never opened.
Why must you not simply apply again?
Because a Tax File Number is issued once per person for life. A second application creates a conflicting record that has to be resolved manually before either can proceed, which turns a retrieval into a delay of weeks.
This is the most common self inflicted problem among returning backpackers, and it is entirely understandable. The old number is missing, the form is free, applying again feels like progress. It is the one action that reliably makes it worse.
What if you genuinely have nothing?
Then it is a retrieval through the ATO, which can be reached on 13 28 61 within Australian business hours or on +61 2 6216 1111 from overseas, or through a tax agent acting for you. Either way it is identity verification, not a new application.
Verification runs on your full legal name exactly as it appears on your passport, your date of birth, your passport number, the passport you held when you first applied if you have since renewed it, and your Australian address history. The renewed passport point catches people out: the record was created against the old document, and both may be needed.
It is harder from overseas, because the identity checks are built around documents and phone numbers an Australian resident has and someone who left two years ago frequently does not.
Where does this bite hardest?
At the point where you actually need it, which is usually one of two moments. Starting a new job, where not having it means 45% withholding until it is supplied. Or claiming superannuation after leaving, where the fund cannot release money to someone it cannot identify.
The super case is the more expensive one, because it stacks with everything else that goes wrong once you are out of the country: a changed address, a closed bank account, a fund that has already reported the balance as unclaimed. Anyone planning to claim your superannuation after leaving Australia should locate their TFN before the flight.
How do you not lose it again?
Store it somewhere that survives a stolen phone and a lost wallet: a password manager or an encrypted note rather than a photo in the camera roll. A paper copy is fine as long as it is kept separately from your passport, since the combination of the two is exactly what identity fraud needs.
Avoid emailing it to yourself in plain text or leaving it in an unlocked notes app. A TFN on its own cannot empty an account, but with a passport scan alongside it, it is enough to open one.
Five minute search or a phone call?
Which one you are facing depends on your own history in Australia. These are the facts that decide it.
- Whether you have ever worked in Australia before, since that is what determines whether a number already exists.
- Whether you have renewed your passport since, which changes what is needed to verify you.
- Whether you are in Australia or overseas, which changes how hard the identity check is.
- Whether you have super sitting with a fund, since that is usually what makes finding it urgent.
- Whether there are prior years you never lodged, which need the same number and are usually refunds waiting.
Once you have it back, any outstanding year can still be lodged as a working holiday tax return, and you can estimate your tax refund for each year you worked.