BAS Due Dates 2026-27

A quarterly BAS is due on the 28th of the month after the quarter ends, except the October to December quarter, which gets an extra month and is due 28 February. A monthly BAS is due on the 21st of the following month. An annual GST return is due 31 October.

Those are the standard dates, and they are the ones the ATO prints. Two things move them. A date landing on a weekend or a public holiday rolls to the next business day, and two separate concessions can push a quarterly date out by two weeks or by roughly four.

Same four quarters, three different sets of dates depending on how the statement gets to the ATO. Every date in the last three columns has the weekend and public holiday rule applied.

Quarter 2 reads the same in all three columns, and that is not a mistake. Its 28 February date already carries a one-month extension over the other three quarters, so neither concession adds anything on top.

The quarter 4 agent date of 25 Aug 2027 carries an ATO caveat: it is to be confirmed when the BAS agent lodgment program for 2027-28 is developed. Treat it as firm enough to plan around and check it again after 1 July 2027.

The 21st of the month after the tax period, all twelve months. Neither the two-week concession nor the agent lodgment program applies to a standard monthly statement, so the only thing that moves a monthly date is the weekend and holiday rule. Three of the twelve move in 2026-27.

One exception sits on the December period. A December monthly BAS for a business client with up to $10 million turnover that reports GST monthly and lodges electronically through a registered agent is not due until 21 Feb 2027, which is a Sunday and so becomes Monday 22 February 2027. A business registered for deferred GST does not get it and lodges by 21 Jan 2027. Schools and associated bodies also lodge their December BAS by 21 January.

Annual reporting is available where you are voluntarily registered for GST and your turnover is under $75,000, or $150,000 for a not-for-profit body. One return, one payment, one date.

Both dates fall in the 2027-28 year and sit past the end of the ATO's published public holiday table, which currently runs to 14 June 2027. They have been checked against weekends and against the state holidays announced so far. Worth knowing if you are in northern Tasmania: Monday 1 November 2027 is Recreation Day there. It is a regional holiday rather than a whole-of-state one, so under the ATO rule it does not move the date, but your bank and your bookkeeper will be shut.

The ATO states it in one line on the BAS due dates page:

If the due date is on a weekend or public holiday, you have until the next business day to lodge and pay.

The definition that matters sits on a different page, in the lodgment program section, and it is the part that catches people out:

A public holiday is defined as a day that is a public holiday for the whole of any state or territory in Australia. This means if a due date falls on a public holiday that is a public holiday for the whole of a state or territory, taxpayers in all states and territories can lodge or pay on the first business day, even if they don't celebrate that public holiday.

Three consequences, and this page applies all three:

1. A holiday in one state moves the date for the whole country. Labour Day in WA is why quarter 2 lands on 2 Mar 2027 rather than 1 March.
2. A regional holiday moves nothing. Recreation Day in northern Tasmania and the Royal Hobart Show are absent from the ATO's tables for exactly that reason.
3. The rule can chain. A Friday holiday followed by a weekend and a Monday holiday pushes to the Tuesday. The ATO's Christmas 2026 rows do this, running 24 December straight through to 29 December.

The dates on this page are checked against the ATO's own public holiday table, and the shift logic reproduces the ATO's published first-business-day column on every row of it. That table runs to 14 June 2027. Dates past that line, meaning quarter 4 and everything in the annual section, are checked against weekends and announced state holidays but not yet against an ATO table.

The ATO sets your cycle from your GST turnover and prints it on the statement. You do not choose it, though you can apply to change it.

If your statement has no GST section at all, only PAYG withholding or a PAYG instalment, it is an instalment activity statement rather than a BAS, and it runs on its own dates. The instalment activity statement guide covers who gets one. PAYG withholding and PAYG instalment deadlines are set out in PAYG due dates.

You do not stack them. If an agent lodges for you, the lodgment program date is your date. If you lodge yourself online, the two-week date is your date. Either way, the date printed on the statement in your online services account is the one the ATO will hold you to, and it is worth checking against this page rather than instead of it.

Two separate consequences. The unpaid amount becomes a tax debt from the day after it fell due, and general interest charge accrues on it daily until the balance clears. Separately, a failure to lodge on time penalty can apply to the statement itself, and that one runs whether or not you owe money, so a nil BAS lodged late can still attract it.

The ATO also gives extra time after a natural disaster, and will discuss a deferral if you ask before the due date rather than after it. Ringing in advance is a materially different conversation.

If the problem is a PAYG instalment sitting on the same statement rather than the GST, varying the instalment is possible on or before the due date and never after, and missed PAYG instalments covers interest and payment plans.