If you’re asking “when is the Q1 BAS due date,” the short answer is 28 October, for the July to September quarter. If you lodge through a registered tax agent, this can be extended to 25 November under the ATO’s lodgment program concession.
For small and medium businesses juggling payroll, superannuation, and day-to-day operations, keeping BAS due dates front of mind is one of the simplest ways to avoid unnecessary ATO penalties and interest charges.
What Is a Q1 BAS and Who Needs to Lodge One?
A Business Activity Statement (BAS) is how GST-registered businesses report and pay their goods and services tax, PAYG withholding, and PAYG instalments to the ATO. Q1 covers the July, August, and September reporting period, the first quarter of the Australian financial year.
If your business is registered for GST and reports quarterly rather than monthly or annually, you’ll need to lodge a Q1 BAS regardless of your turnover, structure, or industry.
What Is the Q1 BAS Due Date for 2026?
The Q1 2026 BAS due date is 28 October 2026, for businesses lodging their own BAS. Businesses using a registered tax or BAS agent typically receive an extended due date of 25 November 2026, provided the agent lodges electronically under the ATO’s agent lodgment program.
This extension is one of several reasons many small businesses choose to work with a registered agent, alongside the accuracy and compliance support they provide.
Quarterly BAS Due Dates 2026: The Full Calendar
| Quarter | Period Covered | Standard Due Date | Tax Agent Concession Due Date |
|---|---|---|---|
| Q1 | July – September 2026 | 28 October 2026 | 25 November 2026 |
| Q2 | October – December 2026 | 28 February 2027 | 28 February 2027 |
| Q3 | January – March 2027 | 28 April 2027 | 26 May 2027 |
| Q4 | April – June 2027 | 28 July 2027 | 25 August 2027 |
Note that Q2 already has a longer lodgment window than the other quarters, due to the December holiday period, so no separate tax agent concession applies. For a fuller breakdown of BAS due dates 2026 Australia, our team has put together a dedicated guide for BAS due dates.
Why Do BAS Due Dates Matter So Much?
Missing a BAS due date isn’t just an administrative headache. The ATO can apply Failure to Lodge (FTL) penalties, calculated in penalty units for each 28-day period a statement is overdue, plus General Interest Charge (GIC) on any outstanding tax debt.
Late lodgment can also affect your standing with the ATO more broadly, including access to payment plans or instalment arrangements down the track. For businesses relying on the instant asset write-off or claiming input tax credits, accurate and timely BAS lodgment also ensures you’re not leaving cash flow benefits on the table.
How Can Small Businesses Stay on Top of BAS Deadlines?
A few practical habits go a long way:
- Set calendar reminders at least two weeks before each due date.
- Reconcile your accounts weekly, not just at quarter end.
- Keep superannuation and PAYG withholding records current throughout the quarter, not compiled after the fact.
- Partner with a registered BAS or tax agent to take advantage of extended due dates and reduce the risk of errors.
If you want a step-by-step walkthrough of the lodgment process itself, our team has also covered this in detail in our guide to BAS lodgement.
Staying Ahead of Every BAS Quarterly Due Date
Q1 sets the tone for the rest of the financial year. Getting your BAS lodged accurately and on time gives you a clearer picture of cash flow and keeps your compliance record clean heading into Q2.
If you’d like support extending your team’s capacity around BAS season, get in touch with Befree to see how we can help you stay ahead of every deadline.