BAS Due Dates 2025-26: Quarterly and Monthly Lodgment Deadlines
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Primary tax-year context: 2025-26
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General information only. Speak with a registered tax or BAS agent for advice.
Missing a BAS due date triggers an automatic penalty. Here are the exact dates for 2025-26, what happens if you miss one, and how to get an extension.
Quarterly BAS due dates 2025-26
Most small businesses lodge quarterly. Here are the legislative due dates, plus the extended dates available to registered tax agent clients.
| Quarter | Period | Self-lodge due date | Tax agent due date |
|---|---|---|---|
| Q1 | 1 Jul – 30 Sep 2025 | 28 October 2025 | 25 November 2025 |
| Q2 | 1 Oct – 31 Dec 2025 | 28 February 2026 | 28 March 2026 |
| Q3 | 1 Jan – 31 Mar 2026 | 28 April 2026 | 26 May 2026 |
| Q4 | 1 Apr – 30 Jun 2026 | 28 July 2026 | 25 August 2026 |
The tax agent due dates apply automatically if you are on a registered agent’s lodgment program. You must be engaged with the agent before the original due date passes to access these extensions.
Monthly BAS due dates
If your GST turnover is $20 million or more, you must lodge monthly. Monthly BAS is due on the 21st of the following month.
Examples:
- July 2025 BAS → due 21 August 2025
- August 2025 BAS → due 21 September 2025
- November 2025 BAS → due 21 December 2025
Exception — December BAS: The December monthly BAS is due 21 February (not 21 January). The ATO gives businesses a longer window over the summer break.
Weekend and public holiday rule
If a due date falls on a weekend or public holiday, the deadline automatically moves to the next business day. This applies to both quarterly and monthly lodgers. Always check the calendar for each specific date — national public holidays and state-specific holidays both count.
Late lodgement penalties
If you miss a BAS due date, the ATO issues a failure to lodge (FTL) penalty automatically.
- The penalty is calculated in units. One penalty unit = $330 in 2025-26.
- You accrue 1 penalty unit per 28-day period (or part thereof) that the BAS remains unlodged.
- The maximum penalty is 5 penalty units ($1,650) for individuals and small businesses.
- Large entities (annual turnover $1M+) face a multiplier — the maximum penalty is $8,250.
The penalty accrues even if you owe no GST. Lodge on time regardless of whether you have anything to pay.
Late payment: General Interest Charge (GIC)
If you lodge on time but don’t pay by the due date, the ATO charges the General Interest Charge (GIC) on unpaid amounts from the due date. The GIC rate is set quarterly — check the ATO website for the current rate. GIC compounds daily, so even a short delay adds up on larger balances.
Lodge and pay together to avoid both penalties.
How to get an extension
Option 1 — Use a registered tax or BAS agent. Registered agents have pre-negotiated lodgment programs with extended due dates built in (see table above). This is the most reliable way to get more time.
Option 2 — Contact the ATO directly. Call the ATO business line before your due date and request a deferral. The ATO can grant extensions in genuine hardship situations (natural disaster, serious illness, system outage). Get the deferral in writing or note the reference number.
Extensions are not automatic. Do not assume a deferral has been granted without confirmation.
Electronic lodgement requirement
Businesses with GST turnover over $10 million must lodge their BAS electronically — paper lodgement is not accepted. Electronic lodgement methods include:
- ATO Online Services for Business
- Standard Business Reporting (SBR) software (Xero, MYOB, QuickBooks, etc.)
- Through a registered BAS or tax agent
Smaller businesses can lodge via paper, Online Services, or through an agent.
Payment methods
Once your BAS is lodged, you can pay via:
- BPAY — biller code on your BAS payment slip
- Direct debit — set up through ATO Online Services
- Credit or debit card — available online, but a card surcharge applies
- Australia Post — in person at any Australia Post outlet using your payment slip
- Electronic funds transfer (EFT) — ATO bank details provided on the payment slip
BPAY and direct debit have no surcharge. Credit card payments incur a fee that cannot be claimed as a tax deduction.
Annual BAS lodgement
Some businesses with a GST turnover below $75,000 elect to report annually. The annual BAS is generally due by 31 October following the end of the financial year, with an extended date available through a registered agent.
Annual lodgers who also withhold PAYG from employees may still need to pay GST quarterly on an instalment basis — check with your agent if this applies.
Sources (verified)
Next step
- Estimate BAS payable with the BAS Calculator
- Reconcile GST in the GST Calculator
- If BAS prep is exposing weak paperwork, standardise invoices and quotes in the branding-ready tools library
- If payroll records are part of the clean-up, use the payroll document hub