Your September Quarter BAS Is Due: What Brisbane Businesses Need to Know

If your business lodges its Business Activity Statement (BAS) quarterly, the September quarter deadline is almost here. Your Q1 BAS, covering 1 July to 30 September 2026, is due on 28 October 2026. Miss it and you risk penalties and interest, but there are also ways to legitimately get more time and less stress.

At FinTax Partners in Greenslopes, we help Brisbane businesses lodge accurate, on-time BAS, manage their GST and cash flow, and avoid the last-minute scramble. Here is what you need to know for this quarter.

The Key Dates for Your Q1 BAS

The due date depends on how you lodge:

• Self-lodging (standard): 28 October 2026
• Self-lodging online (through myGov, ATO online services or SBR-enabled software): 11 November 2026, thanks to an automatic two-week extension
• Lodging through a registered BAS or tax agent electronically: 25 November 2026, under the agent lodgement program

What Your BAS Covers

Your BAS reports your business tax obligations to the ATO for the quarter, which can include:

• GST collected on sales and GST paid on purchases
• PAYG withholding (tax withheld from employee wages)
• PAYG instalments (prepayments towards your income tax)
• Other obligations such as fuel tax credits, where they apply

What Happens If You Lodge Late

Late BAS lodgement can be costly:

• Failure to lodge (FTL) penalty: the ATO can apply one penalty unit for every 28 days (or part) your BAS is overdue, up to five units. From 1 July 2026 a penalty unit is $364, so the maximum is $1,820 per statement for a small business.
• Interest on unpaid amounts: the General Interest Charge (GIC) applies to any BAS liability you do not pay on time. Since 1 July 2025, GIC is no longer tax deductible, so paying late now costs you more in real terms.
  

Common BAS Mistakes to Avoid

• Claiming GST on purchases that do not include GST (for example, some bank fees and government charges)
• Missing GST credits you are entitled to because records are incomplete
• Getting the timing wrong on large purchases or income
• Leaving reconciliation to the last minute, which is where errors creep in
• Forgetting that the payment is due at the same time as the lodgement
  

How FinTax Partners Helps

As registered agents, we prepare and lodge accurate BAS for businesses across Brisbane, reconcile your GST correctly, make sure you claim everything you are entitled to, and give you the agent concession date of 25 November for this quarter. We can also help you smooth out the cash flow so BAS time is never a shock. Whether you are behind, unsure, or just want it off your plate, we can take care of it.

Frequently Asked Questions