BAS due dates 2026: the quarterly and monthly lodgement calendar
Your Business Activity Statement (BAS) is how you report GST, PAYG withholding and PAYG instalments to the ATO. The lodgement date depends on whether you report quarterly or monthly — and on whether you lodge yourself or through a registered agent. Here is the 2026 picture, laid out so you can plan the year ahead instead of reacting the morning a statement is due.
Complia is an organisational tool that tracks dates and preparation steps. It is not tax, legal or financial advice and does not replace your accountant.
Quarterly BAS due dates for 2026
Most small businesses lodge BAS quarterly. The standard ATO due date is the 28th of the month following the end of each quarter, with an extra month for the December quarter to cover the holiday period.
- Quarter 2 (Oct–Dec 2025): due 28 February 2026
- Quarter 3 (Jan–Mar 2026): due 28 April 2026
- Quarter 4 (Apr–Jun 2026): due 28 July 2026
- Quarter 1 (Jul–Sep 2026): due 28 October 2026
Monthly BAS due dates
If you report monthly — common once your GST turnover passes the threshold or if you elect to — each monthly BAS is generally due on the 21st of the following month. There is no quarterly concession on the monthly cycle, so the cadence is relentless and worth automating reminders for.
The registered agent concession
Lodging through a registered BAS or tax agent usually buys you additional time beyond the standard dates above, often around four extra weeks for quarterly lodgers. The exact concession depends on your lodgement program, so confirm the dates that apply to your business with your agent — then put those dates, not the standard ones, on your calendar.
How to stop a BAS deadline sneaking up
The penalty for a late BAS — failure-to-lodge penalties plus general interest charge on unpaid amounts — almost always dwarfs the cost of staying organised. The fix is boring but effective: map each quarter to a date, set a reminder with enough lead time to gather your figures, and work a short preparation checklist before each lodgement. That is exactly what Complia does, built around the real Australian calendar rather than a generic to-do list.
Frequently asked
- When is the December quarter BAS due in 2026?
- The October–December 2025 quarter BAS is generally due 28 February 2026 under the standard ATO concession that adds an extra month over the holiday period.
- Do I get more time if I use a BAS or tax agent?
- Usually yes. Registered agents typically receive lodgement concessions beyond the standard dates. Confirm the exact dates for your business with your agent and track those.
- What happens if I lodge my BAS late?
- The ATO can apply failure-to-lodge penalties and a general interest charge on amounts owing. Staying ahead of the date is far cheaper than catching up after one is missed.
- Is this page tax advice?
- No. This is an organisational guide to help you plan around lodgement dates. It does not replace your accountant or registered agent.
Put this deadline on autopilot.
Complia keeps small Australian businesses ahead of every lodgement and obligation — BAS, super, ASIC — with checklists and reminders built around the real ATO calendar.