Australians doing their own tax return have a quirk of the calendar to factor in this year. The usual 31 October deadline for 2025–26 returns lands on a Saturday in 2026, and under the ATO's long-standing weekend rule, self-lodgers can lodge on the next business day, Monday 2 November, without penalty.

That extra breathing space is real, but it comes with fine print. With a month to go, anyone still to lodge, or still weighing up whether to use a tax agent, has decisions to make well before that weekend.

Why a Saturday deadline doesn't mean a Saturday cut-off

The ATO's general rule is spelled out on its due-dates page: "When a due date falls on a Saturday, Sunday or public holiday, you can lodge or pay on the first business day after without incurring a penalty or general interest charge."

Applied to this year's calendar, the formal due date for individuals lodging their own 2025–26 return stays 31 October 2026. Because that is a Saturday, the practical last day to lodge without penalty becomes Monday 2 November.

The safest reading is to treat 31 October as the target and 2 November as a buffer, not a new deadline. Online systems can slow down close to cut-offs, and a missing payment summary or a query on a pre-filled figure can take longer to sort out than expected.

The tax agent trap: 31 October means 31 October

The weekend rule does not help people who plan to hand their return to a registered tax agent but haven't yet signed up.

Tax agents can generally lodge clients' returns later than 31 October under the ATO's lodgment program. To get that benefit, however, a person needs to be on the agent's client list in time. In a newsroom item for tax professionals on 3 September 2026, the ATO said new clients must be added, and overdue prior-year returns lodged, by 31 October 2026, "not the next business day". Otherwise clients miss the lodgment-program due dates for their 2026 return.

The ATO's October 2026 agent calendar lists 31 October as the "final date to add new clients to your client list to ensure their 2026 tax return is covered by the lodgment program".

Because the cut-off falls on a Saturday, and many practices are closed on weekends, the realistic window for making contact with an agent may close on Friday 30 October.

A hypothetical tale of two late starters

Consider two hypothetical taxpayers, both yet to lodge their 2025–26 returns in late October.

Sam, a salaried worker with straightforward affairs, lodges through myTax on Sunday 1 November. Under the ATO's weekend rule, a return lodged by Monday 2 November is treated as on time, so Sam's lodgment on the Sunday falls inside that window.

Jordan, who has rental income and wants professional help, first calls an accountant on Monday 2 November. Because the agent client-list cut-off was 31 October, with no next-business-day relief, Jordan may not be covered by the agent's lodgment program for the 2026 return. Jordan's return could then be treated as overdue, and the ATO can apply penalties for late lodgment.

These examples are illustrative only. Individual circumstances vary, and anyone unsure where they stand may wish to speak with a registered tax agent or contact the ATO directly before the end of October.

What the ATO is watching before you press 'lodge'

Rushing a return to beat a deadline raises the risk of errors, and the ATO has been clear about its focus this tax time.

In April 2026, the ATO flagged three priority areas: work-related deductions, omitted income, and tax misinformation. Omitted income covers side hustles, cash jobs, interest and rental earnings. In its 27 July 2026 tax time release, Assistant Commissioner Anita Challen's list of "don'ts" included overclaiming, leaving out side-hustle, cash or online income, copying last year's return, and relying on AI, influencer or unverified advice.

The ATO said more than 100 million pieces of pre-fill information were available this year. Contractors in industries covered by the taxable payments annual report were advised to lodge after 28 August, once that data had flowed through.

Self-lodgers claiming working-from-home costs using the fixed-rate method should note it remains 70 cents per hour for 2025–26, under the ATO's practical compliance guideline PCG 2023/1.

Don't claim next year's changes in this year's return

A common trap this season is mixing up income years. The new $1,000 standard deduction for work-related expenses, sometimes called the instant work deduction, is enacted law but applies from the 2026–27 income year. It cannot be claimed in 2025–26 returns, and the ATO said as much in its July messaging.

Similarly, the lower 15% tax rate on income between $18,201 and $45,000 applies from 1 July 2026. Returns being lodged now are assessed at the 2025–26 rate of 16% for that bracket.

Scam activity is also elevated around deadlines. In September 2026 the ATO warned of malware emails referring to "payment updates" or an "income statement review". It says the links in these emails install remote-desktop software that gives scammers access to a device. Logging in directly through myGov or the ATO app, rather than via links in emails or texts, is a simple precaution.

Key dates to watch

As at 27 August 2026, more than 6.3 million individual returns had been lodged, according to ATO data, with more than 3.5 million of them self-prepared. That leaves a sizeable group still to go.

Key dates now in view:

  • Friday 30 October: the last weekday before the agent client-list cut-off.
  • Saturday 31 October: the formal due date for self-lodgers, and the hard cut-off for joining an agent's lodgment program.
  • Monday 2 November: the last day self-lodgers can lodge without penalty under the weekend rule.

The ATO says most returns are processed within 12 business days. For those who miss the deadline entirely, contacting the ATO or a registered tax agent sooner rather than later may help limit the consequences.