Tax & GST

BAS Due Dates Australia 2026: When to Lodge Your Business Activity Statement

Missing a BAS deadline means ATO penalties and interest charges. Here are all the BAS due dates for 2026, whether you lodge quarterly or monthly.

Quick Answer

Most small businesses lodge quarterly. The due date is the 28th of the month after each quarter ends. If you use a registered tax agent, you get an extra 4 weeks.

Quarterly BAS due dates 2025–26

Quarter	Period	Due Date (self-lodge)	Due Date (tax agent)
Q1 2025–26	Jul – Sep 2025	28 October 2025	25 November 2025
Q2 2025–26	Oct – Dec 2025	28 February 2026	28 February 2026
Q3 2025–26	Jan – Mar 2026	28 April 2026	26 May 2026
Q4 2025–26	Apr – Jun 2026	28 July 2026	25 August 2026

Monthly BAS due dates

Monthly lodgers must lodge and pay within 21 days of the end of each month. For example:

January BAS → due 21 February
February BAS → due 21 March
March BAS → due 21 April
June BAS → due 21 July

Monthly lodgement is mandatory if your annual GST turnover is $20 million or more. Most small businesses lodge quarterly.

What's in a BAS?

Your BAS summarises:

GST collected from your sales
GST credits you can claim on business purchases
PAYG withholding (tax withheld from employees)
PAYG instalments (income tax prepayments for your own income)

Penalties for late BAS lodgement

The ATO applies a Failure to Lodge (FTL) penalty for late BAS submissions. In 2026, each penalty unit is $313. The penalty starts at one unit ($313) and increases by one unit for every 28-day period it remains outstanding, up to a maximum of $1,565.

On top of this, the ATO charges the General Interest Charge (GIC) on any unpaid amount — currently around 11% annually. Lodge on time, even if you can't pay the full amount immediately.

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Frequently asked questions

When is the next BAS due in Australia 2026?

For quarterly lodgers, Q4 2025-26 (April-June 2026) BAS is due 28 July 2026. If you lodge through a registered tax agent, you may have until 25 August 2026. Monthly lodgers must lodge within 21 days of the end of each month.

What happens if I miss my BAS due date?

Missing your BAS due date triggers a Failure to Lodge (FTL) penalty. The penalty is one penalty unit ($313 in 2026) for each 28-day period (or part thereof) the lodgement is late, up to a maximum of five penalty units ($1,565). Interest also accrues on unpaid amounts.

Can I get an extension on my BAS lodgement?

Yes. You can request a deferral through your ATO online services account or by calling the ATO on 13 28 66. Extensions are not guaranteed but the ATO is generally reasonable for first-time requests with a genuine reason.

Do sole traders need to lodge a BAS?

Only if you are registered for GST. If your turnover is under $75,000 and you are not registered for GST, you do not need to lodge a BAS. Once you register for GST, BAS lodgement is mandatory.