BAS Due Dates 2026-27: Lodging Your First BAS and What Happens If You’re Late

The BAS due dates for 2026-27 are 28 October 2026, 28 February 2027, 28 April 2027 and 28 July 2027 for quarterly lodgers, and the 21st of the following month for monthly lodgers. A registered tax or BAS agent can get you about four extra weeks on most quarters, but the concession has conditions, and a first BAS may get no extra time at all.

Most new businesses meet their first BAS the hard way. GST registration felt like admin, the quarter flew past, and the ATO reminder landed in an inbox nobody checks. Very soon “when is it due?” becomes “what will being late cost me?”.

What are the BAS due dates for 2026-27?

Quarter	Period	Due date (lodge yourself)	Due date via a BAS or tax agent (electronic)
Q1	July to September 2026	28 October 2026	25 November 2026
Q2	October to December 2026	28 February 2027, a Sunday, so Tuesday 2 March 2027 (Monday 1 March is Labour Day in WA)	No extra time
Q3	January to March 2027	28 April 2027	26 May 2027
Q4	April to June 2027	28 July 2027	25 August 2027 (the ATO lists this date as to be confirmed)

A due date that falls on a weekend or public holiday moves to the next business day. A public holiday counts if it applies across a whole state or territory, and it moves the date for everyone. That rule is why the December quarter is due Tuesday 2 March 2027: 28 February 2027 is a Sunday and Monday 1 March 2027 is Labour Day in Western Australia.

When is a monthly BAS due, and who lodges monthly?

A monthly BAS is due on the 21st of the month after the reporting month. December is the exception. The December monthly BAS is due 21 January, or 21 February if you lodge electronically through an agent and your GST turnover is up to $10 million.

Monthly reporting is required once your GST turnover reaches $20 million, and the ATO can also direct you to report monthly. Everyone else can generally report quarterly, and some choose monthly for cash flow or record-keeping reasons. When to Move to Monthly BAS Reporting covers the choice, and What Is a Business Activity Statement (BAS)? covers what goes on the statement itself.

When is your first BAS due?

Your first BAS covers the period from the date your GST registration takes effect to the end of that quarter or month, and it falls due on the normal date for that period. Register for GST from 10 August and your first BAS covers 10 August to 30 September, due 28 October. It won’t necessarily cover a full quarter.

Do not assume your first BAS gets the agent extension. The ATO’s agent lodgment program applies the later dates to statements generated after your previous one was lodged electronically, and it warns that a first activity statement may need to be lodged by the earlier due date. Check the due date shown in Online services for business, or ask your agent, before you rely on the extra weeks.

If your GST registration is backdated, every period from the new start date needs a BAS. You must register within 21 days of becoming required to, and the ATO can backdate a registration by up to four years. If you registered late, it can set the start date at the date you were required to register. From that date you owe GST on your taxable sales, even where you didn’t charge customers GST.

The start date also decides which purchases count. GST credits can only be claimed for purchases made from the date your registration takes effect, so they can go in your first BAS even with no sales, while purchases made before that date generally miss out. Our accountants check the start date before a first BAS is lodged, and some new businesses ask the ATO to start their registration earlier so their setup purchases fall inside it.

When does the ATO send your BAS?

The ATO generates your BAS before it is due. If you lodge online and the ATO has your email address, it emails a reminder 21 days before the due date. For 2026-27 the quarterly generation dates are 6 September 2026, 6 December 2026, 7 March 2027 and 6 June 2027.

A reminder sent to an old email address, or to a myGov inbox nobody opens, is still a reminder. Keep your ATO contact details current.

Do you have to lodge a BAS if you had no sales?

Yes. If you are registered for GST and the ATO has issued a BAS, you must lodge it even when every amount is nil. A nil BAS takes minutes online, or you can lodge it through the ATO’s automated phone service on 13 72 26, 24 hours a day. The ATO doesn’t know you had no sales until you tell it, on the statement, by the date.

How much extra time can you get, with or without an agent?

If you receive and lodge your quarterly BAS online yourself, you may qualify for an extra two weeks to lodge and pay the September, March and June quarters. You don’t apply for it. If you qualify, the later date shows on your BAS. It doesn’t cover monthly BAS or the December quarter. Check the date on your BAS before you count on the two weeks.

A registered tax or BAS agent can lodge most quarterly statements about four weeks after the standard date, as the table above shows. Three conditions catch people out:

• the December quarter has no concession for anyone, because its due date already includes an extension
• the agent concession generally needs your previous statement lodged electronically, so a first BAS may miss out
• the ATO can ask for earlier lodgment if you have a history of lodging or paying late

What Is a BAS Agent? covers what an agent does and when to use one.

What happens if you lodge your BAS late?

Two separate costs can apply. The failure to lodge on time penalty, or FTL penalty, is about lodging late. The general interest charge, or GIC, is about paying late. GIC is calculated daily on the unpaid amount and compounds, and the rate for October to December 2026 is 11.51% a year.

The ATO says it generally does not apply an FTL penalty for an isolated late lodgment and usually contacts you first. A pattern of late lodgment, or ignoring reminders, changes that. It also generally won’t issue an FTL penalty for a late BAS that results in a refund or a nil amount, unless the penalty was applied before you lodged or you are a large withholder. Neither “the ATO always fines you” nor “one late BAS is fine” is safe to assume.

GIC incurred on or after 1 July 2025 can’t be claimed as a tax deduction for income years starting on or after that date, even if the debt relates to an earlier year. FTL penalties can’t be deducted either.

How much is the late BAS penalty?

FTL penalty = 1 penalty unit × each 28-day period (or part) the BAS is late, capped at 5 penalty units.

A penalty unit is $364 where the late lodgment occurred on or after 1 July 2026, and $330 from 7 November 2024 to 30 June 2026.

Days late	28-day periods	Base penalty (most small businesses)
1 to 28	1	$364
29 to 56	2	$728
57 to 84	3	$1,092
85 to 112	4	$1,456
113 or more	5 (cap)	$1,820

The base penalty applies to individuals and small withholders. It doubles if you are a medium withholder (more than $25,000 withheld a year) or your GST turnover or assessable income is between $1 million and $20 million. It is five times higher if you are a large withholder (more than $1 million withheld) or your turnover or income is $20 million or more.

Worked example: a late first BAS

Preston registers their design studio for GST from 1 August 2026 and lodges quarterly. Their first BAS covers 1 August to 30 September. Preston receives and lodges it online and qualifies for the two-week concession, so the BAS is due Wednesday 11 November 2026. They have no agent, miss the date, and lodge online on Monday 21 December 2026 owing $4,200 in GST that they can’t pay yet.

• Preston is 40 days late (11 November to 21 December), which is 2 periods of 28 days or part.
• The FTL penalty, if the ATO applies one, is 2 × $364 = $728. The refund or nil exception doesn’t help because Preston owes GST.
• GIC starts on the due date, 11 November, at the October to December 2026 daily rate of 0.03153425% (11.51% a year). On $4,200 that is about $1.32 a day ($4,200 × 0.0003153425 = $1.3244).
• GIC compounds daily, so after 40 days it comes to about $53 ($4,200 × (1.0003153425^40 − 1) = $53.30). It keeps running until the debt is paid, and from 1 January 2027 the next quarter’s rate applies.
• The ATO may not apply the penalty for an isolated first miss, especially because Preston lodged before any demand arrived.
• Lodging stopped the penalty clock even though they couldn’t pay, and the debt can now go on a payment plan.

Missed the 28 October 2026 BAS? What to do this week

1. Lodge the BAS now, even if it is nil or you can’t pay.
2. Check whether a later date applies. Online self-lodgers who qualify for the two-week concession have until 11 November 2026, and agent clients may have until 25 November 2026.
3. Pay what you can, then set up a payment plan for the rest.
4. Keep any ATO letters and note the date you lodged.
5. Once you have lodged, ask about remission of any penalty or interest if something serious stopped you lodging on time.

Can you ask the ATO for an extension after the due date?

A lodgment deferral exists, but the bar is high. Deferrals are for exceptional or unforeseen circumstances, like natural disasters, serious illness or losing access to your records. Forgetting the date is not on the list. Ask before the due date. The ATO only considers a later request if you explain what stopped you asking in time.

• You can’t ask for one before the BAS has been generated.
• Agents can self-assess a short deferral, up to 14 days for monthly and 21 days for quarterly BAS, for an existing client’s first deferral request on that BAS, made no more than 3 business days after the original due date.
• Once the BAS is already late, our accountants lodge everything outstanding first, then ask the ATO to remit the penalty or interest, with an explanation and evidence of what happened. The ATO expects outstanding lodgments to be up to date before it considers a penalty remission request.
• Remission is the ATO’s decision. Serious illness, a natural disaster or missing information from a third party can support a request. Being busy, a holiday or not receiving a reminder usually won’t. The ATO also asks why you or your agent didn’t request more time before the due date.

What if you can lodge but can’t pay?

Lodge on time anyway. Late lodgment can add a penalty and late payment adds interest. Lodging on time removes the penalty risk.

If you owe $200,000 or less, you may be able to set up a payment plan in Online services for business. Larger debts mean contacting the ATO. GIC keeps running while you are on a plan, so every extra month on it adds interest. BAS Payment Plans has the step-by-step.

What do Lawpath customers ask about BAS?

These are the BAS questions we hear most from customers in consultations, sales calls and support messages.

1. Who lodges my BAS, is it in my plan, and how do I get ready?
2. How do I fill it in and lodge it?
3. I’ve missed one or more BAS. How do I catch up?
4. When is it due, and do agents really get extra time?
5. Which period does my first BAS cover?

The myths our accountants correct most often: no sales means no BAS (wrong), and a BAS prepared in the accounting software counts as lodged (it doesn’t). Refunds cause confusion too. The ATO generally won’t issue a late lodgment penalty when a late BAS ends in a refund or nil result, but a penalty applied before you lodge can still stand, and the exception doesn’t cover a BAS where you owe tax.

BAS due date checklist

1. Confirm your GST registration date and reporting cycle.
2. Put every 2026-27 due date in your calendar.
3. Check your ATO contact email and myGov inbox are current.
4. Decide whether you will lodge yourself or through an agent.
5. If you use an agent, confirm your due dates with them, especially for a first BAS.
6. Reconcile sales, purchases and GST before the due date.
7. Lodge even when the BAS is nil.
8. Pay by the due date, or set up a payment plan the same day.
9. Missed a date? Lodge now and keep a record of when.
10. After you lodge, ask about remission if something outside your control caused the delay.

Rather not track BAS dates yourself? A Lawpath accountant can lodge your BAS each quarter and keep you inside the agent program.

When should you get advice?

• your first BAS is due and you are unsure which period it covers
• you have missed one or more BAS
• you have received an FTL penalty notice or a lodgment demand
• you owe more than you can pay
• your GST turnover is getting close to $20 million
• you registered for GST late, or backdated the registration
• you are not sure what goes on the BAS, such as PAYG withholding, PAYG instalments or fuel tax credits

Frequently asked questions

When is the BAS due for the July to September 2026 quarter?

It was due 28 October 2026 if you lodge yourself, or 25 November 2026 through a registered agent lodging electronically.

When is my first BAS due?

Your first BAS covers the period from your GST registration date to the end of that quarter or month, due on the normal date for that period. Don’t assume the agent extension applies, because the ATO says a first activity statement may need to be lodged by the earlier due date.

When is a monthly BAS due?

On the 21st of the month after the reporting month. December is the exception, due 21 January, or 21 February through an agent for businesses with turnover up to $10 million.

Do BAS agents get extra time to lodge?

Yes, about four extra weeks on most quarters. The December quarter gets none, and the concession generally needs your previous statement lodged electronically.

Why is there no extension for the December quarter?

Its due date already includes an extension. The ATO moved it from late January to late February.

Do I have to lodge a BAS if I had no sales?

Yes. If you are registered for GST and the ATO has issued a BAS, you must lodge it even when every amount is nil.

What is the penalty for lodging a BAS late?

If the ATO applies one, most small businesses pay $364 for each 28-day period or part the BAS is late, capped at $1,820. Medium and large withholders pay two or five times that.

Can I get an extension on my BAS after the due date?

A deferral is possible for exceptional or unforeseen circumstances like natural disasters or serious illness, and you should ask before the due date. Forgetting the date doesn’t qualify. If the BAS is already late, lodge it, then ask the ATO for penalty remission.

What should I do if I can’t pay my BAS?

Lodge on time anyway, then set up a payment plan for what you owe. Lodging late can add a penalty on top of the interest.

What happens if my BAS due date falls on a weekend?

It moves to the next business day, and a public holiday across any whole state or territory counts. In 2026-27, 28 February 2027 is a Sunday and Monday 1 March 2027 is Labour Day in WA, so the December quarter is due Tuesday 2 March 2027.

Missed one? Lodge this week

BAS dates don’t wait for busy founders. Put the four quarterly dates in your calendar, treat the agent concession as a privilege with conditions, and if you have already missed one, lodge this week even without the money.

A Lawpath accountant can handle it. BAS lodgement covers a one-off statement, BAS and tax services keeps every quarter on time, and managed accounting takes the books off your plate. If a penalty or tax debt has already landed, our tax debt help team can step in.