BAS Due Dates: When Your Activity Statement Is Actually Due

Most business owners know roughly when their BAS is due and get it wrong by a fortnight in one direction or the other. Here are the actual dates, plus the extensions you may already be entitled to.

Quarterly BAS due dates

If you report quarterly, which most small businesses do, these are your dates for the 2026 to 2027 financial year:

• Quarter 1, July to September 2026: due 28 October 2026
• Quarter 2, October to December 2026: due 28 February 2027
• Quarter 3, January to March 2027: due 28 April 2027
• Quarter 4, April to June 2027: due 28 July 2027

The same pattern repeats every year. Quarter 2 gets the long gap because it already has an extra month built in for Christmas.

The extra two weeks

If you lodge your quarterly BAS online, you generally get an extra two weeks to lodge and pay.

There is one exception, and it is the one people assume works the other way. The concession does not apply to Quarter 2. The 28 February date already includes a one month extension, so there is no further two weeks on top of it. If you have been assuming mid March for the December quarter, you have been late.

A registered tax or BAS agent can also access the ATO lodgment program, which carries its own concessional dates. Those are usually later again. If you lodge through an agent, ask them for your actual dates rather than working off the public ones.

Monthly BAS

If you report monthly, your BAS is due on the 21st of the following month. September lodges 21 October, October lodges 21 November, and so on.

Monthly reporting is compulsory once your GST turnover reaches $20 million. Below that you can choose it, and some businesses do because it keeps the cash flow rhythm tighter and stops one large quarterly bill landing at a bad time.

Annual GST return

If you registered for GST voluntarily and your GST turnover is under $75,000, you may be able to report annually. That return is due 31 October.

When the date lands on a weekend

If a due date falls on a weekend or a public holiday, it moves to the next business day. That matters more in WA than elsewhere, because a few of our public holidays do not line up with the eastern states. Check the date rather than assuming.

What happens if you are late

Two separate things, and people often only think about the first.

Failure to lodge penalty. The ATO can apply a penalty for each 28 day period the statement is overdue, up to a cap. It is charged per statement, so several late quarters add up quickly.

General interest charge. Separately, interest accrues on any unpaid amount from the due date. The rate is set quarterly and it is higher than most business overdrafts.

The important point: lodging and paying are two different obligations. If you cannot pay, lodge anyway. Lodging on time and arranging a payment plan puts you in a far better position than going quiet. The ATO treats a business that has lodged and asked for help very differently from one that has done neither.

The habit that actually fixes this

Chasing a BAS deadline is a symptom, not the problem. The problem is usually that the bookkeeping is done in the week the statement is due rather than through the quarter.

Three things that make the difference:

• Reconcile weekly, not quarterly. Twenty minutes a week beats two days of panic four times a year, and the numbers are accurate enough to make decisions on in between.
• Put the GST somewhere else. The GST you collect is not your money. Moving it to a separate account as it comes in is the single most effective cash flow habit a small business can build.
• Diarise the date, not the month. Put the actual due date in the calendar with a reminder two weeks out.

Business owners who do these three things stop thinking about BAS entirely. It becomes an administrative step rather than an event.

Help with the lodgement

We handle BAS and GST lodgement for Perth businesses as part of our tax and compliance work, including the quarterly reconciliation that makes the statement accurate rather than just submitted. If cash flow around BAS time is the real issue, that is a virtual CFO conversation rather than a compliance one.

This article is general information only. It does not take your circumstances into account and it is not tax advice. Due dates and concessions can change, so check the current dates with the ATO or with us before relying on them.