Quarterly BAS due dates follow a fixed rhythm: 28 October, 28 February, 28 April, 28 July. Here are the exact dates for the 2026-27 financial year, plus the rules that move them.
The dates
| Quarter | Period covered | Due date |
|---|---|---|
| Q1 | 1 July to 30 September 2026 | 28 October 2026 |
| Q2 | 1 October to 31 December 2026 | 1 March 2027 |
| Q3 | 1 January to 31 March 2027 | 28 April 2027 |
| Q4 | 1 April to 30 June 2027 | 28 July 2027 |
Why Q2 says 1 March, not 28 February
28 February 2027 falls on a Sunday. When a due date lands on a weekend or public holiday, it moves to the next business day. That's the one quirk in the table worth knowing, because it catches people who set a recurring reminder for the 28th.
If you lodge monthly
Monthly lodgers report by the 21st of the following month, every month. Most sole traders under $20 million turnover lodge quarterly, so if you never chose monthly, the quarterly table is yours.
A note on agent extensions
If you lodge through a registered tax or BAS agent, their lodgement program usually gives several extra weeks beyond the dates above. If you lodge yourself through myGov, the table is your deadline, full stop.
What happens if you're late
- A failure-to-lodge penalty can apply, charged per 28-day period late. For a small business it starts at $330 per period and rises the longer you leave it.
- Interest accrues on any unpaid amount from the due date.
- The ATO doesn't chase you before the deadline. No reminder arrives. The dates above are on you.
The rule that saves money: always lodge on time, even if you can't pay. The penalty is for late lodgement, not for owing. Lodge, then contact the ATO to arrange a payment plan.
Never think about the date again
The ClearQuarter kit tags every transaction to its quarter automatically, so when a due date approaches you already know exactly which period you're lodging and what the numbers are. Pair it with a phone reminder a week before each date and BAS stops being a scramble.