BAS Lodgement Deadlines 2025–26, Every Due Date for Australian Small Businesses

2025–26 BAS Lodgement Deadlines at a Glance

Most Australian small businesses lodge their BAS quarterly. The table below shows every due date for the 2025–26 financial year, both the standard deadline and the extended deadline available to clients of a registered BAS agent.

Agent extension dates are subject to ATO confirmation. Dates shown are standard for the 2025–26 year. Annual BAS date applies to businesses voluntarily registered for GST with turnover under $75,000.

The Agent Extension, What It Is and How to Get It

Every client of a registered BAS agent automatically receives an additional 4-week lodgement extension on quarterly BAS deadlines. This means your BAS isn't due until approximately 4 weeks after the standard deadline, at no cost, no application required.

There's one condition: you must be registered as a client of the agent before the standard deadline passes. If you only engage a BAS agent after the due date, the extension does not apply to that quarter.

For small businesses with complex transactions, particularly in trades or allied health where quarterly data takes time to compile, the agent extension makes a real practical difference.

What Happens If You Miss the BAS Deadline

The ATO's Failure to Lodge (FTL) penalty applies from the day after your BAS deadline passes:

• $330 for each 28-day period (or part thereof) the BAS is overdue
• Maximum $1,650 for small businesses (turnover under $1 million)
• Medium businesses: maximum $3,300. Large businesses: maximum $16,500
• ATO may also issue a default assessment, estimating your liability, often higher than actual
• Interest applies to any unpaid tax from the standard due date

Monthly BAS Lodgement, When Does It Apply?

Most small businesses lodge quarterly. You may be required to lodge monthly if:

• Your annual GST turnover exceeds $20 million (mandatory monthly)
• You are on a GST instalment plan but have chosen to pay monthly
• The ATO has placed you on monthly reporting due to compliance history

Monthly BAS for a $20M+ turnover business is due on the 21st of the following month. Most small businesses in Mornington Peninsula and regional Victoria lodge quarterly.

Annual BAS, Who Qualifies?

Businesses with GST turnover under $75,000 (the GST registration threshold) are not required to register for GST at all. If you are voluntarily registered for GST with turnover under $75,000, you may be eligible to lodge annually rather than quarterly, with the 2025–26 annual BAS due by 31 October 2026.

For most growing small businesses turning over $300k+, quarterly lodgement is standard. Annual BAS is mainly relevant for very small businesses or investment properties registered for GST.

How to Never Miss a BAS Deadline Again

The simplest solution: engage a registered BAS agent. Once your books are maintained by a registered agent:

• You automatically receive the 4-week agent extension every quarter
• Your BAS is prepared and lodged without you needing to track the date
• You receive a lodgement confirmation and the amount payable or refundable
• ATO correspondence is handled on your behalf

For a Mornington Peninsula or Mornington Peninsula small business turning over $300k+, the cost of a registered BAS agent bookkeeper is typically recovered many times over in time saved, late penalty avoidance, and correct GST coding.