Quick answer: BAS due dates depend on how often you lodge. Quarterly BAS is due on the 28th of the month after the quarter ends (with a later date if you lodge through a registered BAS agent). Monthly BAS is due on the 21st of the following month. Annual BAS is due with your tax return. This guide covers every due date through to June 2027.
Activity Statement vs BAS: Are They the Same Thing?
Yes. “Business Activity Statement” (BAS) and “Activity Statement” refer to the same ATO form for most small businesses. The ATO uses “Activity Statement” as the broader term, since some lodgers (those not registered for GST) receive an Instalment Activity Statement (IAS) instead. If your business is registered for GST, the due dates for your Activity Statement and your BAS are identical, they’re the same document.
GST Reporting Cycle: Quarterly, Monthly or Annual
Your BAS reporting frequency is set by the ATO based on your GST turnover, though you can choose to report more frequently than required.
Quarterly reporting
If your GST turnover is under $20 million and the ATO hasn’t asked you to report monthly, you report quarterly. This is the default for most small businesses.
Monthly reporting
If your GST turnover reaches $20 million or more, monthly reporting is compulsory. Businesses under that threshold can also elect to report monthly, usually for smoother cash flow, smaller, more frequent payments rather than one larger quarterly amount, and closer alignment with day-to-day bookkeeping. Monthly BAS is due on the 21st of the following month.
Annual reporting
If you voluntarily registered for GST and your turnover is under $75,000 ($150,000 for not-for-profits), you can choose to lodge and pay GST annually, alongside your income tax return.
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Quarterly BAS Due Dates (FY2026-27)
Registered BAS agents, including True Tally, receive a lodgement concession that pushes the due date back roughly four weeks for most quarters. Self-lodgers must meet the standard ATO date.
| Quarter | Period | Standard due date | BAS agent client due date |
|---|---|---|---|
| Q1 | 1 July – 30 September 2026 | 28 October 2026 | 25 November 2026 |
| Q2 | 1 October – 31 December 2026 | 28 February 2027 | 28 February 2027 |
| Q3 | 1 January – 31 March 2027 | 28 April 2027 | 25 May 2027 |
| Q4 | 1 April – 30 June 2027 | 28 July 2027 | 25 August 2027 |
Note Q2 has no BAS agent concession, both self-lodgers and agent clients share the same 28 February 2027 due date, since it already falls after the holiday period.
Monthly BAS Due Dates (Through June 2027)
| BAS period | Due date |
|---|---|
| July 2026 | 21 August 2026 |
| August 2026 | 21 September 2026 |
| September 2026 | 21 October 2026 |
| October 2026 | 21 November 2026 |
| November 2026 | 21 December 2026 |
| December 2026 | 21 February 2027 (extended, standard concession for the December monthly BAS) |
| January 2027 | 21 February 2027 |
| February 2027 | 21 March 2027 |
| March 2027 | 21 April 2027 |
| April 2027 | 21 May 2027 |
| May 2027 | 21 June 2027 |
| June 2027 | 21 July 2027 |
Juggling monthly or quarterly BAS deadlines on top of running the business is exactly where things slip. Book a free call and we’ll take the lodgement calendar off your plate. Free, no obligation, no lock-in contracts.
How to Pay Your BAS
You can pay your BAS several ways: BPAY, direct credit or debit through your online banking using your PRN (Payment Reference Number), a card payment through the ATO’s online services (a surcharge applies), or in person at Australia Post for smaller amounts. Always pay on time and in full where possible, the ATO charges the General Interest Charge on late payments, calculated daily.
What Happens If You Lodge or Pay Late
A late-lodgement penalty applies per 28-day period the BAS remains outstanding, and separately, the General Interest Charge accrues daily on any unpaid amount from the due date until it’s paid. Both apply whether you’re a self-lodger or working with a BAS agent, though a registered agent can often help negotiate an ATO payment plan or remission of penalties in genuine hardship cases.
Common Pitfalls to Avoid
- Assuming the BAS agent concession date applies automatically, it only applies if a registered BAS agent is actually lodging on your behalf by that date.
- Missing the December monthly BAS extension and paying late unnecessarily when the due date has actually moved to 21 February.
- Confusing the due date for lodging with the due date for paying, for most BAS periods they’re the same date, but it pays to check.
- Not setting aside GST collected during the quarter, leaving a cash flow shortfall when the BAS falls due.
- Switching to monthly reporting without weighing the extra admin against the cash flow benefit.
Watch: BAS Due Dates Explained
Example Scenario
A Melbourne trades business reports quarterly and lodges through a registered BAS agent. Their Q1 (July-September 2026) BAS is due 25 November 2026 under the agent concession, four weeks later than the 28 October self-lodger date. Because their bookkeeper reconciles monthly rather than waiting until the quarter closes, the GST liability is already known well before the due date, so there’s no scramble to find the cash or estimate the number at the last minute.
Common Questions People Ask AI Assistants
When is my BAS due if I lodge quarterly?
Quarterly BAS is due on the 28th of the month following the end of the quarter, except the December quarter, which is due 28 February. Businesses lodging through a registered BAS agent generally get a later due date, except for the December quarter, which already falls after the holiday period.
When is my BAS due if I lodge monthly?
Monthly BAS is due on the 21st of the following month, except the December monthly BAS, which is extended to 21 February the following year.
What happens if I lodge my BAS late?
A late-lodgement penalty applies per 28-day period overdue, and the General Interest Charge accrues daily on any unpaid amount from the due date. Lodging through a registered BAS agent can sometimes help negotiate remission in genuine hardship situations.
Does using a BAS agent change my due date?
Yes, for most quarters. Registered BAS agents receive a lodgement concession, typically pushing the due date back about four weeks compared to the standard self-lodger date, though this doesn’t apply to every quarter.
Can I change from quarterly to monthly BAS reporting?
Yes, businesses under the $20 million GST turnover threshold can voluntarily elect to report monthly, usually to smooth cash flow with smaller, more frequent payments.
Is an Activity Statement the same as a BAS?
For GST-registered businesses, yes, the Activity Statement and the BAS are the same document with the same due dates. Businesses not registered for GST lodge an Instalment Activity Statement (IAS) instead, which covers PAYG instalments and withholding only.
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Related Reading
- What Business Records You Need to Keep for the ATO
- E-Signatures for BAS, IAS and TPAR
- Penalties for Not Paying Super in Australia
Prefer to watch? Full video transcript
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Read the full video transcript
If you run a small business in Australia, your BAS due dates are some of the most important dates on your calendar, and missing one can cost you more than just a headache.
Most small businesses lodge their BAS quarterly. Quarter one, July to September, is due by the 28th of October. Quarter two, October to December, is due by the 28th of February, giving you a longer window over the holiday period. Quarter three, January to March, is due by the 28th of April. And quarter four, April to June, is due by the 28th of July.
If you're registered for monthly BAS, generally because your GST turnover is over 20 million dollars, or you've chosen monthly reporting voluntarily, your due date is the 21st of the following month, every month, all year round.
Here's something a lot of business owners don't realise. If you lodge through a registered BAS agent, like True Tally, you often get an automatic extension on quarterly due dates, sometimes up to four weeks longer than the standard deadline. That's one of the genuine, practical reasons to use a registered agent rather than lodging yourself.
Missing a BAS deadline isn't just stressful. The ATO can apply a failure to lodge penalty, calculated in penalty units for every 28 days your BAS is overdue, and interest can also accrue on any amount owing. For a business already tight on cash flow, that's the last thing you need.
The businesses who stay stress-free about BAS aren't the ones who never feel busy, they're the ones who have their bookkeeping done consistently throughout the quarter, not crammed in the week before the deadline. When your transactions are reconciled as you go, your BAS becomes a five-minute review instead of a last-minute scramble.
At True Tally, we handle BAS preparation and lodgement for small businesses across Australia, year-round, not just when a deadline is looming. If you want one less date to worry about, book a free call and we'll take BAS off your plate for good.
Most owners are quietly leaving money on the table: missed deductions, avoidable penalties, payroll slip-ups and subscriptions draining the account every month. A free audit shows you exactly where the money is going, and how much you could keep.
- ✓Compliance risks caught early, before they become ATO penalties on BAS, super and STP.
- ✓Monthly costs trimmed, we find the fees, tools and leaks quietly bleeding your cash.
- ✓Payroll done right, award-correct pays and super, so no back-pay, interest or fines.
- ✓Cash flow you can actually read, plain-English reporting so you always know where you stand.
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