BAS Due Dates 2026–27 Australia: Quarterly & Monthly GST Deadlines
Quick answer: Quarterly BAS for 2026–27 are due on the 28th of the month after each quarter ends: 28 October 2026, 28 February 2027, 28 April 2027, and 28 July 2027. Monthly BAS are due on the 21st of the following month.
When Are Quarterly BAS Due Dates 2026–27?
Most small businesses report GST quarterly. Your BAS is due on the 28th of the month after the quarter ends:
| Quarter | Period | BAS due date |
| Q1 | 1 Jul – 30 Sep 2026 | 28 Oct 2026 (Wed) |
| Q2 | 1 Oct – 31 Dec 2026 | 28 Feb 2027* (Sun → Mon 1 Mar 2027) |
| Q3 | 1 Jan – 31 Mar 2027 | 28 Apr 2027 (Wed) |
| Q4 | 1 Apr – 30 Jun 2027 | 28 Jul 2027 (Wed) |
*The December quarter already includes a one-month extension, so no further concession applies. If a due date falls on a weekend or public holiday, you have until the next business day to lodge and pay.
When Are Monthly BAS Due In 2026–27?
Businesses with GST turnover of $20 million or more must lodge monthly. Monthly BAS are due on the 21st of the month after the reporting period:
| Month | BAS due date | Month | BAS due date |
| Jul 2026 | 21 Aug 2026 (Fri) | Jan 2027 | 21 Feb 2027 → Mon 22 Feb 2027 |
| Aug 2026 | 21 Sep 2026 (Mon) | Feb 2027 | 21 Mar 2027 → Mon 22 Mar 2027 |
| Sep 2026 | 21 Oct 2026 (Wed) | Mar 2027 | 21 Apr 2027 (Wed) |
| Oct 2026 | 21 Nov 2026 → Mon 23 Nov 2026 | Apr 2027 | 21 May 2027 (Fri) |
| Nov 2026 | 21 Dec 2026 (Mon) | May 2027 | 21 Jun 2027 (Mon) |
| Dec 2026 | 21 Jan 2027 (Thu) | Jun 2027 | 21 Jul 2027 (Wed) |
What Is The 2-Week Online Lodgment Extension?
If you lodge your own BAS online (rather than through a tax agent), you may be eligible for an extra two weeks to lodge and pay your quarterly BAS. Except for the December quarter (Q2), which already includes a one-month extension, this concession gives you more breathing room.
Which reporting cycle are you on?
| Cycle | Who | Due |
| Monthly | GST turnover $20m or more (mandatory); others can elect | 21st of following month |
| Quarterly | Default for most businesses | 28th of month after quarter |
| Annual | Eligible small businesses (PAYG instalment conditions apply) | 31 Oct (or 28 Feb if no tax return required) |
What happens if you lodge late?
The ATO can apply a failure to lodge penalty and charge general interest on unpaid amounts from the due date. If you are struggling to pay on time, contact the ATO before the deadline — payment plans are often available and lodging on time (even without payment) reduces penalties.
What Are Common Questions About BAS Due Dates?
When is the Q1 2026–27 BAS due?
28 October 2026, for the quarter 1 July – 30 September 2026.
When is the December quarter BAS due?
28 February 2027 (the December quarter already includes a one-month extension). Since 28 February 2027 is a Sunday, you have until Monday 1 March 2027.
When are monthly BAS due?
On the 21st of the month following the reporting period, for example, the July 2026 monthly BAS is due on 21 August 2026.
Do I get extra time if I lodge online myself?
You may get an extra two weeks for quarterly BAS lodged online, except for the December quarter. Monthly BAS do not get the extension.
What if the due date falls on a weekend?
You have until the next business day to lodge and pay. For example, the 21 November 2026 monthly deadline shifts to Monday 23 November 2026.
Who has to lodge BAS monthly?
Businesses with GST turnover of $20 million or more must lodge monthly. Smaller businesses can elect to lodge monthly if they prefer.
When is the annual BAS due?
31 October following the financial year, or 28 February if you are not required to lodge an income tax return.
What are the penalties for late BAS lodgment?
The ATO may impose a failure-to-lodge penalty and charge interest on unpaid tax from the due date. Lodge on time even if you cannot pay in full, and ask about a payment plan.
Last verified: 3 October 2026. Sources: ATO: Due dates for lodging and paying your BAS. See also our Australian GST reporting guide and free GST calculators.
