BAS due dates in Australia for 2026-27

BAS due dates in Australia follow a set quarterly rhythm, and the deadline that applies to you depends on how you lodge. Lodge on paper and you get the base date. Lodge online and the ATO gives you about two extra weeks. Lodge through a registered BAS agent and you usually get about four extra weeks. Here is the full 2026-27 calendar.

Quarterly BAS due dates for 2026-27

Quarter 2 is the odd one out. Its base date already includes a summer extension past the holidays, so there is no further extension for online or agent lodgement. The standard 28 February date falls on a Sunday in 2027, which pushes it to Monday 1 March.

Monthly BAS

If you report monthly, usually because GST turnover is 20 million dollars or more, or because you have chosen monthly reporting, your BAS is due on the 21st of the following month. December's BAS is due 21 January.

What happens if you lodge late

The ATO can apply a failure to lodge penalty that grows the longer the statement sits unlodged, and interest can apply to unpaid amounts. If a deadline has already passed, the best move is to lodge as soon as possible and talk to the ATO or your agent about a payment plan if the bill is a problem. A late lodgement with a payment plan is a far better position than silence.

How to make BAS time uneventful

• Keep the file reconciled through the quarter. A BAS prepared from a reconciled file is quick. One prepared from a shoebox is not.
• Check the odd GST items. Bank fees, insurance premiums and overseas subscriptions are commonly coded wrong and quietly skew the GST figure.
• Use the agent dates deliberately. The extra weeks through a registered agent are breathing room for review, not procrastination time.

Dates come from the ATO's published lodgement program for 2026-27. The ATO can vary dates for specific taxpayers, so the dates on your own BAS or in your myGov or Online services account always take precedence.