BAS Due Dates 2026–27: Quarterly and Monthly Lodgement Calendar

Missing a BAS due date can mean failure-to-lodge penalties and general interest on late payments. Below are the standard ATO due dates for the 2026–27 financial year, plus a simple checklist to work backwards from each one.

Always confirm your own obligations on ato.gov.au or with your registered tax or BAS agent — some businesses have different cycles or deferrals.

Quarterly BAS due dates (lodging yourself)

• Q1 (July–September 2026): 28 October 2026
• Q2 (October–December 2026): 28 February 2027 — a Sunday, so it moves to the next business day, 1 March 2027
• Q3 (January–March 2027): 28 April 2027
• Q4 (April–June 2027): 28 July 2027

Monthly BAS

Monthly lodgers generally lodge and pay by the 21st day of the following month. For example, the September 2026 BAS is due 21 October 2026. December is an exception for many monthly lodgers — check the ATO calendar for the extended date.

Lodging through a registered agent

Registered tax and BAS agents who lodge electronically may have later due dates under the ATO’s lodgment program — for example, Q1 is commonly due 25 November rather than 28 October. Eligibility depends on the agent and client, so confirm with your agent before relying on an extension.

Work backwards: a two-week prep checklist

• Two weeks out: bank, credit card, and clearing accounts reconciled to quarter end
• Ten days out: uncategorised and suspense transactions cleared
• One week out: GST codes reviewed on sales and purchases; capital purchases checked
• Five days out: payroll and STP figures tied out to W1 and W2 labels
• Three days out: BAS draft reviewed by the person who will lodge
• Due date: lodge and pay (or confirm the payment arrangement)

If you are already behind

Start with reconciliation — nothing else on the BAS can be trusted until the bank balances. If the backlog is months long, a catch-up job on the oldest periods first is usually faster than trying to fix everything at once.

We prepare BAS drafts and reconciliations inside your Xero or MYOB; lodgement stays with you or your registered agent.