Yes, you can absolutely switch your tax-free threshold claim from one employer to another at any time during the financial year. 

In Australia, the first $18,200 you earn annually is tax-free, but you are generally only allowed to claim this threshold from one payer at a time (typically your highest-paying or primary job). If your work layout shifts—for example, your side retail job becomes your main source of income and your old office job scales back—moving the threshold ensures you maintain maximum weekly cash flow without facing a surprise bill at tax time. 

1. Step-by-Step: How to Legally Execute the Switch

To successfully shift the threshold without creating a payroll conflict, you must notify both employers. Your employers’ custom accounting software cannot communicate with each other; it is your responsibility to update your status.

You can manage this switch using two different methods:

Method A: The Modern Online Way (Via myGov)

1. Log into your myGov account and select your linked Australian Taxation Office (ATO) service. 
2. From the main menu, navigate to Employment > Employment details.
3. Locate your current employers listed on screen. Click the arrow next to the employer you want to change and select Update.
4. Follow the prompts to toggle your tax-free threshold settings on or off. The system will electronically transmit the updated withholding data directly to your employers.

Method B: The Traditional Paper Way (Via Payroll)

If your employer handles payroll manually, you will need to submit physical forms to your HR departments:

• Step 1 (The Old Job): Give your old employer a Withholding Declaration (Form NAT 3093). On this form, answer NO to the question asking if you want to claim the tax-free threshold. This instructs their system to start withholding tax from the very first dollar you earn. 
• Step 2 (The New Job): Give your new primary employer a separate Withholding Declaration (or a brand new TFN Declaration Form if you are onboarding). Answer YES to claim the tax-free threshold. 

2. The Timing Trap: Avoiding an End-of-Year Tax Debt

While executing the switch is mathematically straightforward, the exact week you choose to submit the forms matters.

Because tax is calculated based on your total combined annual income at the end of the financial year (June 30), changing your threshold mid-year can result in a tax shortfall if your previous job underpaid tax while the threshold was applied to it.

[ Threshold Split Mid-Year ] ──► [ Both Employers Apply % Exemption Pro-Rata ] ──► [ Annual Income Consolidated ] ──► [ Potential ATO Debt ]

How to Shield Yourself from an ATO Shortfall:

If you have been claiming the threshold at a job for 6 months and then switch it to a different job for the remaining 6 months, both systems will calculate your weekly pay as though you are only earning within a low-income bracket. When the ATO combines your data lines at tax time, they may discover you were undertaxed overall.

The Compliance Fix: If you are worried about an unexpected tax bill, you can request your secondary employer to withhold an additional, voluntary flat amount of tax from your pay each cycle (e.g., an extra $20 per week). You can specify this dollar amount directly in Section 7 of the Withholding Declaration Form. 

Tax Threshold Structuring Matrix