BAS due dates in Australia follow a set quarterly rhythm, and the deadline that applies to you depends on your reporting cycle and eligibility for lodgement arrangements. The table shows standard quarterly dates and eligible online dates. Confirm any agent arrangement and the date in your ATO account before relying on extra time.
Quarterly BAS due dates for 2026-27
| Quarter | Period | Standard | Eligible online lodgement | Through a BAS agent |
|---|---|---|---|---|
| Q1 | Jul to Sep 2026 | 28 Oct 2026 | 11 Nov 2026 | Confirm with your agent |
| Q2 | Oct to Dec 2026 | 1 Mar 2027 | 1 Mar 2027 | 1 Mar 2027 |
| Q3 | Jan to Mar 2027 | 28 Apr 2027 | 12 May 2027 | Confirm with your agent |
| Q4 | Apr to Jun 2027 | 28 Jul 2027 | 11 Aug 2027 | Confirm with your agent |
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.
Sterix is a registered BAS agent. Clients on our BAS agent service have their statements prepared from a reconciled file. We confirm the applicable dates and agree when records and approval are needed.
The standard dates and online eligibility rules follow the ATO's BAS due date guidance, with weekends allowed for. The date on your own BAS or in your ATO account takes precedence. Confirm agent dates directly rather than assuming an extension.
Work backwards from the due date
Agree a date for supplying missing receipts, resolving queries and approving the statement. Keep payment responsibility clear. A lodgement calendar works best when the preparation steps are scheduled too.
Read what a registered BAS agent does before deciding who will prepare and lodge your statement.
For more practical answers, browse our bookkeeping guides or read what to check when choosing a bookkeeper.
This article is general information for Australian small business owners. It is not tax, legal or financial advice. Your situation is specific, so talk to your registered BAS agent, tax agent or adviser before acting on anything here.