BAS due dates for 2026-27: every quarterly deadline for sole traders

The four quarterly due dates

Quarterly BAS are due on the 28th of the month after the quarter ends:

• Quarter 1, 1 July to 30 September 2026: due 28 October 2026 (Wednesday).
• Quarter 2, 1 October to 31 December 2026: due 28 February 2027. That is a Sunday, so the effective deadline is Monday 1 March 2027.
• Quarter 3, 1 January to 31 March 2027: due 28 April 2027 (Wednesday).
• Quarter 4, 1 April to 30 June 2027: due 28 July 2027 (Wednesday).

Both lodgement and payment are due on the same day. The ATO usually makes the statement available in online services a couple of weeks before the quarter ends, so you can lodge as soon as the last transaction of the quarter is in.

When a due date falls on a weekend or public holiday

If the due date is a weekend or public holiday, you have until the next business day. That is why the Q2 date of 28 February 2027, a Sunday, effectively becomes Monday 1 March 2027. Public holidays vary by state, so if the 28th is a holiday where you live, check the ATO’s published date rather than assuming.

A good habit is to treat the 28th as the deadline regardless and lodge a few days before, because payments made on the day can take until the next business day to clear.

Extra time through a registered agent

If a registered BAS or tax agent lodges for you electronically, the ATO generally allows about four extra weeks on the Q1, Q3 and Q4 statements, moving them to late November, late May and late August respectively. The Q2 statement already has a built-in extension because of the holiday period, which is why it is due 28 February rather than 28 January, and agents do not get further time on it.

The extension only applies if you are on the agent’s lodgement program. If you prepare in software and lodge yourself, the standard dates apply. Check the ATO site or your agent for the exact concession dates each year.

Monthly and annual lodgers

Monthly BAS are due on the 21st of the following month, so the July 2026 statement is due 21 August 2026 and so on. Monthly is compulsory above $20 million turnover and optional below it.

If you registered for GST voluntarily and your turnover is under $75,000, you may be eligible to lodge an annual GST return instead. It is generally due when your tax return is due, or 28 February if you do not have to lodge a tax return. Check your eligibility in ATO online services.

Other dates in the same year

• 28 July 2026: the last BAS of 2025-26 (April to June 2026 quarter).
• 28 August 2026: Taxable Payments Annual Report for 2025-26, if you pay contractors in a covered industry. See TPAR explained.
• 31 October 2026: 2025-26 income tax return if you lodge it yourself. It falls on a Saturday, so Monday 2 November 2026. Registered agents usually have much later dates for their clients, often into May 2027.
• 30 June 2027: end of the financial year. Super contributions you want to deduct in 2026-27 must reach your fund by then.
• 28 July 2027: Q4 BAS, the first deadline of 2027-28.

PAYG instalments for quarterly payers are due on the same dates as the BAS and appear on the same form.

If you cannot pay by the date

Lodge anyway. The failure-to-lodge penalty is separate from interest on unpaid amounts, and lodging on time keeps you out of it. Then set up a payment plan in ATO online services; small business plans for modest amounts can usually be arranged online without a phone call. General interest charge applies to the outstanding balance.

The better fix is to set the GST aside as you go. One eleventh of every GST-inclusive payment you receive is not yours, and moving it to a separate account each week means the BAS bill is already sitting there in October. See setting aside money for tax.