Quarterly lodgers, the next standard due date is the 28th of the month following the end of the quarter (28 October, 28 February, 28 April, 28 July). Monthly lodgers, it's the 21st of the following month. Online self-lodgers may get an extra two weeks on Q1, Q3 and Q4. Registered agents work to the tax agent lodgment program, which pushes deadlines further out again.
BAS Due Dates 2025–26: Quarterly & Monthly Lodgement Calendar
Written by James Woods, Managing Director
Written by James Woods, Managing Director
At a glance
Quarterly and monthly BAS due dates for FY2025–26
Online and tax agent lodgement deadlines
Annual reporting options and late penalties
How unpaid invoices can affect BAS cash flow
Table of Contents
Quarterly BAS due dates FY2025-26
If a due date lands on a weekend or public holiday, lodgement rolls to the next business day. Source: ATO due dates for lodging and paying your BAS.
What's on this page
We'll start with the dates, then cover the rules behind each deadline.
You'll find the full FY2025-26 lodgement calendar for quarterly and monthly BAS, plus annual GST return dates, the two-week online concession, the tax agent lodgment program, and what the ATO does if you miss a deadline.
Built for accountants, bookkeepers, and small business owners looking up the next due date. Not a rewrite of the ATO site. Just the numbers you need with the working shown.
We refresh this page each January and July, when the ATO republishes its dates and when penalty units change.
Monthly BAS due dates
If your GST turnover hits $20 million or more, monthly reporting is mandatory. Some smaller entities also elect monthly by choice. The rule is straightforward. The monthly BAS is due on the 21st of the following month.
The December exception is the one to remember. December's monthly BAS gets pushed to 21 February, aligned with the summer close-down. Every other month follows the 21st rule, shifted forward if the 21st isn't a business day.
Annual BAS reporting
Annual reporting is on the table if you're voluntarily registered for GST and your GST turnover sits under $75,000, or under $150,000 for not-for-profits. It suits sole traders and micro-entities who'd rather deal with one lodgement a year than four.
The annual GST return is due 28 February following the end of the financial year. If you're not required to lodge an income tax return, it's due 31 October instead. Source: ATO due dates for lodging and paying your BAS.
Agent vs self-lodge: extra time explained
This part often causes the most confusion because there are three different lodgement deadlines.
Self-lodgers who submit online through myGov or Online services for business pick up an automatic two-week concession for Q1, Q3 and Q4. Q2 misses out because it already runs an eight-week lodgement window over the summer period.
Registered agents work to the tax agent lodgment program, which stretches most quarterly deadlines further again. It's the schedule used by accounting and bookkeeping professionals lodging on behalf of clients.
The online concession only applies if you lodge and pay electronically and meet the ATO's concession terms. Miss the electronic requirement and you drop back to the standard due date.
What is a Business Activity Statement?
A BAS is the form you use to report and pay several tax obligations in one go. GST collected on sales, GST credits on purchases, PAYG withholding for employee wages, PAYG instalments toward your income tax, and where relevant, FBT instalments, wine equalisation tax and luxury car tax.
If you're registered for GST, you lodge a BAS. Frequency comes down to turnover. Quarterly is the default for most small and medium businesses. Monthly kicks in at $20 million GST turnover. Annual is available for voluntary registrants under the small-business threshold.
Penalties for late BAS lodgement
Two things happen when you miss a BAS deadline. The ATO can apply a Failure to Lodge (FTL) penalty, and it charges General Interest Charge (GIC) on any unpaid amounts.
The FTL penalty is worked out in penalty units. A small entity cops one penalty unit for every 28-day period, or part period, the statement is overdue, capped at five units. Medium entities pay double. Large entities pay five times the base amount.
From 1 July 2026, the Commonwealth penalty unit is $364. Offences committed before that date use the earlier rate ($330 from 7 November 2024 to 30 June 2026).
Worked example. A small entity lodges its September 2026 quarterly BAS 90 days late. That's four full 28-day periods overdue.
FTL penalty: 4 units × $364 = $1,456
Plus GIC on any unpaid GST or PAYG amount, compounded daily at the ATO's published rate
GIC bites hardest when there's a large unpaid balance sitting behind the late lodgement. Full detail: ATO FTL penalty guidance.
When unpaid invoices squeeze your BAS
Here's the trap most business owners walk into at quarter-end. If you report GST on an accrual basis, you owe GST on every invoice you've raised, whether the customer has paid you or not. PAYG withholding for your team doesn't pause because a debtor is dragging their feet.
So you end up funding the ATO out of pocket for revenue you haven't collected. One or two slow-paying customers can turn a routine BAS into a genuine cash flow problem.
The bigger issue is overdue invoices. Once accounts start drifting past 60 days, BAS can quickly become a cash flow problem. Escalating an overdue account promptly, whether through internal follow-up or small business debt collection when overdue invoices are hurting quarter-end cash flow, keeps the gap between invoiced revenue and cash in the bank from blowing out around BAS time.
FAQs
The ATO can apply a Failure to Lodge penalty of one penalty unit per 28-day period late, capped at five units for a small entity. At $364 per unit from 1 July 2026, that's up to $1,820 for a small entity, more for medium and large. General Interest Charge accrues daily on any unpaid amount until it's cleared.
Sometimes. The ATO can grant a deferral for a genuine reason such as illness, natural disaster, or a serious business disruption. Request it before the due date, not after. Lodging through a registered tax or BAS agent also gives you the lodgment program dates automatically, which is a de facto extension for most quarters.
GST turnover decides. Under $20 million and you report quarterly by default. $20 million or more and monthly is mandatory. Voluntarily GST-registered with turnover under $75,000 ($150,000 for NFPs) and you can elect annual reporting.
One penalty unit per 28 days overdue, up to five units, for a small entity. Medium entities pay double, large entities pay five times. The penalty unit is $364 from 1 July 2026. Plus GIC on any unpaid tax.
You can request a change through Online services for business, or ask your registered agent to do it. The ATO will confirm whether you're eligible based on turnover and lodgement history. Changes usually kick in from the start of the next reporting period.
Yes. A nil BAS still has to be lodged if you're registered for GST. You can lodge it online in under a minute, or by phone through the ATO's automated service. Skipping it triggers the same FTL penalty as any other missed lodgement. If you're planning quarter-end close-out, our [new financial year debt recovery process](https://www.ecollect.com.au/blog/new-financial-year-debt-recovery-process) covers the debtor side of the same exercise.
References
James Woods
Managing Director
James has operated businesses since his late teens including windsurfer hire (1977 – 1981), yacht charter (1990 – 2001), motor accident repairs (1984 – 1989) and debt recovery (2002 to the present). He holds a B.A. and LL.B. from Monash University and was admitted as a lawyer in 1983. He is also a Graduate of the Australian Institute of Company Directors.
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