When is my BAS due?

The four quarterly dates

The ATO publishes the standard dates in ATO: Due dates for lodging and paying your BAS. For a business reporting quarterly:

If the 28th lands on a Saturday, Sunday or a public holiday, you have until the next business day. That is a real extension, not a grace period, and it is worth checking against your state's holidays rather than assuming — a long weekend in one state is not a long weekend in another.

Monthly and annual BAS

Monthly lodgers report on the 21st of the following month: June's activity statement is due 21 July, and so on. Monthly reporting is compulsory if your GST turnover is $20 million or more, or if the ATO has told you to report monthly. Smaller businesses can choose it — usually because they want the GST credits flowing back sooner, or because their bookkeeping is monthly anyway.

There is also an annual option. If you are voluntarily registered for GST because your turnover is under the threshold, an annual GST return may be available: the ATO lists 31 October for businesses that also lodge a tax return, and 28 February where no tax return is required. ATO: Business activity statements (BAS) explains which registrations put an activity statement in your path in the first place.

The two-week online concession

If you lodge your quarterly activity statement online, and the ATO receives it online, you generally get an extra two weeks to lodge and pay. The catch is in ATO: Two week lodgment concession, terms and conditions: the concession applies to quarters 1, 3 and 4 — not the December quarter, and not monthly activity statements or quarterly PAYG instalment notices. The reason the December quarter is excluded is that those lodgers already get eight weeks, because the 28 February date is two months after the quarter ends rather than the usual one.

If a tax or BAS agent lodges for you

Registered agents work to a separate lodgment program with later dates, published each year. For the 2026–27 program, ATO: BAS agent lodgment program 2026–27 lists Q1 moved to 25 November 2026, Q3 to 26 May 2027 and Q4 to 25 August 2027 — the December quarter does not move. If your accountant lodges your BAS, the date that matters is the one in their program, but the underlying obligation is still yours: the ATO holds the business responsible, not the agent.

What you are actually reporting

A BAS is not just GST. Depending on your registrations, the same form can carry:

• GST — the GST you collected on sales, less the GST credits on your business purchases.
• PAYG withholding — tax withheld from wages you paid to employees, and from payments to contractors who did not quote an ABN.
• PAYG instalments — prepayments of your own income tax, if the ATO has put you on the instalment system.

That is why the amount on the form is rarely just "GST on sales". A sole trader with no employees may only ever fill in the GST labels; a business with staff is reporting two or three things at once.

Practical habits that stop the dates biting

Three things make the deadlines ordinary rather than stressful:

1. Reconcile monthly, lodge quarterly. If your records are up to date at the end of each month, the BAS is a summary rather than a reconstruction.
2. Put the four dates in your calendar with a reminder a week early — including the public holiday shift, which moves the date you actually have to pay.
3. Plan the cash, not just the form. The GST on your sales is money you have been holding since you invoiced; the amount due is not a surprise if you have kept it aside.

If you set the money aside as you invoice and lodge before the date, the BAS stops being an event. The BAS due date finder will tell you which date applies to you once you pick the quarter and your state, including the weekend and holiday shift.

If you are not registered for GST yet, that question comes first — How to register for GST in Australia covers when registration becomes compulsory and how the threshold is measured.