BAS due dates for 2026–27: every date, and how to get more time

Your BAS due date depends on three things: whether you report quarterly or monthly, whether you lodge online yourself, and whether a registered tax or BAS agent lodges for you. The same quarter can have three different due dates. This guide sets out every date for the 2026–27 financial year in one place, checked against the ATO's published program, and explains what happens if you miss one.

The next one is close. The September 2026 quarter is due Wednesday 28 October 2026 if you lodge it yourself on paper, two weeks later if you lodge online yourself, and Wednesday 25 November 2026 if your agent lodges it electronically.

What are the quarterly BAS due dates for 2026–27?

Most small businesses report quarterly. You report quarterly if your GST turnover is under $20 million, unless the ATO has directed you to report monthly or you've chosen to.

Notes on the table

• The two-week concession dates are our calculation from the ATO's rule (two weeks after the 28th). The ATO applies the concession automatically if you qualify and shows the updated date on your statement. Check your statement.
• The agent dates are from the ATO's lodgment program for 2026–27. The ATO notes the Q4 date will be confirmed in the 2027–28 program.
• The December quarter gets no extra time under either concession, because its standard due date already includes an extra month for the Christmas shutdown.
• 28 February 2027 is a Sunday. The ATO lets you lodge and pay on the next business day without penalty, which is Monday 1 March 2027. That Monday is Labour Day in Western Australia, so WA businesses should check their statement.
• Lodging on paper means you don't get the online concession, and if your previous statement was lodged on paper, an agent may not get the program date either.

What are the monthly BAS due dates for 2026–27?

You report monthly if your GST turnover is $20 million or more, if the ATO directs you to, or if you choose to (some businesses do, to get GST refunds faster).

A monthly BAS is due on the 21st of the following month. When the 21st falls on a weekend, you can lodge and pay on the next business day.

Monthly concessions are narrow. The two-week online concession doesn't apply to monthly statements, and the agent program doesn't extend standard monthly statements either. The one exception is December: for business clients with turnover up to $10 million who report GST monthly and lodge electronically through an agent, the December BAS is due 21 February instead of 21 January. In 2027, 21 February is a Sunday, so the practical date is Monday 22 February 2027.

How do the tax agent lodgment program dates work?

Registered tax agents and BAS agents have an ATO lodgment program that gives their clients extra time, on conditions:

• The statement must be lodged electronically by the agent, through the ATO's agent online services or practitioner lodgment service.
• It applies to quarterly statements (and the December monthly statement, above).
• Your previous activity statement must have been lodged electronically. If it was lodged on paper, or this is your first statement, an earlier date can apply.
• The extra time covers payment too, not just lodgment.
• The agent must have you on their client list before the standard due date. Engaging an agent the day after 28 October won't move Q1 to 25 November.

The program is designed to let agents spread their work, so it comes with an expectation that the agent lodges on time across their whole client list. Good agents treat the program date as the deadline, not the target.

Key point: If you're thinking about moving your BAS to an agent to get more time, do it at least a few weeks before the next standard due date, so your record is linked to the agent in time.

When is the annual GST return due?

If you're registered for GST voluntarily and your GST turnover is under $75,000 ($150,000 for non-profits), you can elect to report GST annually. You'll still report PAYG withholding and instalments on activity statements if you have them.

• The annual GST return is generally due 31 October after the end of the financial year. For the 2025–26 year, 31 October 2026 is a Saturday, so you can lodge and pay on Monday 2 November 2026.
• If you aren't required to lodge an income tax return, it's due 28 February after the year ends.
• If an agent lodges your tax return, different dates may apply under their program.

Annual reporting suits small, steady businesses. If you're growing towards $75,000, you'll need to move to quarterly once you're required to be registered. Our guide to GST registration explains the thresholds.

What happens if my BAS is late?

Two separate costs, plus a much bigger risk for company directors.

1. Failure to lodge penalty (lodging late)

The ATO can apply a failure to lodge penalty of one penalty unit for each 28 days (or part) that a BAS is late, up to five penalty units. A penalty unit is $364 for failures on or after 1 July 2026. For a small business, the maximum per late BAS is $1,820. Medium and large entities face multiples of that.

In practice, the ATO often doesn't apply the penalty to a business that lodges voluntarily and has a good record. It's much more likely after the ATO has chased you, or where several statements are outstanding.

2. General interest charge (paying late)

Any amount not paid by the due date attracts the general interest charge, calculated daily and compounding. The GIC rate is 11.51% a year for October to December 2026 (it was 11.43% for July to September 2026; the ATO resets it quarterly). GIC incurred from 1 July 2025 is not tax deductible, which makes an ATO debt expensive finance.

3. Director penalties (for companies)

Company directors can become personally liable for the company's unpaid PAYG withholding, GST and super guarantee charge through a director penalty notice. If those amounts aren't reported within three months of the due date, the director can't escape the penalty by putting the company into administration or liquidation. Lodging on time, even when you can't pay, keeps those options open. Our guide to director penalty notices explains how they work.

Watch out: Lodge on time even if you can't pay. A lodged BAS with a payment plan costs interest. An unlodged BAS can cost penalties, and for directors, personal liability.

What to do if you can't pay

• Lodge by the due date regardless.
• Pay what you can.
• Set up a payment plan. For smaller debts the ATO lets you do this online. See our guide to ATO payment plans.
• If you're behind on several lodgments, talk to us about overdue tax and ATO debt. Catching up voluntarily is almost always better than waiting for the ATO.

What does a BAS actually cover?

A business activity statement can include several obligations, and each has its own rules:

Businesses with GST turnover under $10 million report GST using Simpler BAS, which needs only total sales, GST on sales and GST on purchases.

Super is no longer on the BAS cycle. From 1 July 2026, Payday Super requires super to reach employees' funds within seven business days of each payday. If you used to pay super quarterly with your BAS, read our Payday Super guide.

Your 2026–27 BAS calendar at a glance

For a quarterly business using a registered agent, here's the year:

Self-lodging online? Use Wed 11 November 2026, Mon 1 March 2027, Wed 12 May 2027 and Wed 11 August 2027. Lodging on paper? Use the standard 28th dates.

Payday Super contributions, PAYG withholding through Single Touch Payroll, and annual returns all sit alongside these. Your tax returns, BAS, payroll and ASIC calendar is something we keep for every client.

How to keep BAS from becoming a quarterly scramble

1. Keep your books current. A Xero file reconciled weekly makes the BAS a review, not a project. See our Xero bookkeeping service.
2. Put the GST aside. A separate account for GST and PAYG withholding, topped up weekly, means the BAS bill is never a surprise.
3. Check before you lodge. Most BAS errors are coding errors: GST claimed on bank fees, insurance stamp duty, overseas subscriptions or private purchases.
4. Diarise the agent date, then aim for two weeks earlier.
5. Fix mistakes in the next BAS where you can. Small errors can often be corrected in a later statement instead of revising the old one, within limits set by the ATO.

How BPAG handles your BAS

On our plans, BAS lodgement is included. Your books are kept current in Xero, and before every lodgement our BAS pre-lodgement check agent looks for GST coding and label errors: missing tax invoices, GST claimed where none was charged, wrong treatment of insurance, bank fees and overseas purchases. Every figure on the BAS workpaper is traced to the transactions behind it. Your client manager reviews the workpaper and approves it before you see it, and nothing is lodged until you've signed off. After lodgement, our post-BAS review agent turns unusual movements into questions for you, so problems surface early.

The agents draft and check; a qualified accountant reviews and signs off. Lodgement through us means you get the agent program dates, and a person tells you what you owe weeks before it's due. See our BAS and GST service for details.

If your business is simple, your books are tidy and you're comfortable with the ATO's online services, lodging yourself online is perfectly reasonable and gets you the two-week concession. Many sole traders do exactly that.

General information only, current as at 18 October 2026. It is not personal tax, legal or financial product advice and doesn't take your circumstances into account. Talk to us before you act. Where a recommendation needs a licensed financial adviser or a solicitor, we work alongside them.