BAS due dates: the full Australian lodgement calendar

What is a BAS, and why do due dates matter?

A Business Activity Statement (BAS) is the form GST-registered businesses use to report GST, PAYG withholding, PAYG instalments and a few other obligations to the Australian Taxation Office (ATO). If you are unfamiliar with the form itself, Gimbla's BAS glossary entry explains what a Business Activity Statement covers and who needs to lodge one.

The due date depends on your reporting cycle — monthly, quarterly or annual — and on whether you lodge yourself or through a registered tax or BAS agent. Getting the date wrong doesn't just risk a penalty; it can also delay any GST refund you're owed.

Monthly BAS due dates

If you report monthly, your BAS is due on the 21st day of the following month. There is no registered-agent concession for monthly BAS lodgements.

The December monthly BAS gets an extended due date of 21 February to account for the holiday period.

Quarterly BAS due dates

Most small businesses report quarterly. If you lodge your own BAS (not through a registered agent), the standard due date is the 28th of the month following the end of the quarter.

Quarter 2 already has a longer gap built in — from 31 December to 28 February — so it doesn't get a further agent concession.

Registered agent concession dates

If a registered tax or BAS agent prepares and lodges your quarterly BAS electronically, you generally get extra time on three of the four quarters.

Concession dates are set by the ATO and can shift slightly, or move to the next business day if a due date falls on a weekend or public holiday. Confirm the current dates with your agent or the ATO before relying on them.

Annual GST reporting due dates

Businesses that elect to report GST annually generally lodge their Annual GST Return at the same time as their income tax return. If you're not required to lodge an income tax return, the due date is usually 28 February following the end of the financial year.

What exactly goes on a BAS?

Read Gimbla's glossary entry on the Business Activity Statement for a plain-English breakdown of GST, PAYG withholding, PAYG instalments and the other fields you'll see on the form.

Read the BAS glossary entry

What happens if you lodge late?

• The ATO can apply a Failure To Lodge (FTL) penalty, calculated in penalty units for each 28-day period the BAS remains outstanding, up to a maximum.
• General interest charge (GIC) can accrue on any amount you owe from the due date, even if you lodge on time but pay late.
• Repeated late lodgement can affect your standing with the ATO and, for agent-lodged clients, your eligibility for future lodgement concessions.
• The ATO can, and often does, remit penalties for a first-time or one-off lateness with a reasonable explanation — contact them before the due date if you know you'll be late.

A simple way to stay ahead of BAS due dates

• Add every relevant due date — including the agent concession dates if they apply to you — to a shared calendar as soon as a new financial year starts.
• Reconcile bank accounts and review GST coding throughout the quarter rather than in the final week.
• Set aside GST collected and PAYG withheld in a separate account so the amount owing on lodgement day isn't a surprise.
• If you use a registered agent, confirm which concession date applies to your specific BAS — some agents have their own internal deadlines ahead of the ATO's.

Due dates and concession periods can change, and individual circumstances vary. This guide provides general information, not tax advice — check current dates with the ATO or your registered tax or BAS agent.

Official BAS resources

• ATO: Business activity statements (BAS)
• ATO: Due dates for lodging and paying your BAS
• ATO: Lodgment program due dates for agents

Due dates were reviewed on 2 September 2026.