Staying on top of your compliance deadlines keeps your business running smoothly and avoids unnecessary penalties. Here are the key dates October 2026 business owners need on their calendar.
21 October
Lodge and pay your September 2026 monthly Business Activity Statement (BAS).
If you report GST monthly, this is your deadline to lodge and pay for the September period.
28 October
Lodge and pay your Quarter 1, 2026-27 activity statement (July to September), if you are lodging by paper or without a registered agent extension.
31 October
Lodge your 2025-26 tax return if you are not using a registered tax agent. Because 31 October falls on a Saturday this year, self-lodgers effectively have until the next business day to get it in.
If you are using a registered tax agent, you must be added to their client list by 31 October. The next business day does not apply to this cutoff. Some new clients also need to complete the agent nomination process before they can be added, so the last working day to arrange this is Friday 30 October. Once you are on an agent’s client list, your lodgment deadline generally extends well into 2027.
If any of these dates apply to your business and you are not sure where things stand, now is the time to check, not the week they are due.
Optima Partners’ Business Advisory team helps Australian business owners stay ahead of dates like these, so nothing is a last-minute scramble. If you would like a hand, get in touch with us here.
