Most Australians know 31 October as “tax day”, but that single date hides a set of different deadlines that apply depending on who lodges your return, what you earned, and whether you have anything outstanding from prior years. Get the category wrong and the first you hear about it is a penalty notice.
This guide sets out the dates that apply to the 2025-26 income year, what changes if you lodge through a registered tax agent, and what it actually costs if you miss the cut-off.
Key ATO tax return deadlines at a glance
Individual self-lodged tax returns for the 2025-26 income year are due by 31 October 2026. If you are on a registered tax agent’s client list before that date, you generally get a later lodgement date, in many cases as far out as 15 May 2027. The registration is what unlocks the extension, not the lodgement itself.
| Date | What is due |
|---|---|
| 1 July 2026 | Lodgement season opens for 2025-26 returns |
| 28 October 2026 | Quarter 1 BAS (July to September 2026) |
| 31 October 2026 | Individual self-lodged returns; last day to join an agent’s client list; returns for individuals and trusts with a prior-year return outstanding as at 30 June 2026 |
| 28 February 2027 | Quarter 2 BAS (October to December 2026) |
| 31 March 2027 | Individuals and trusts whose latest return showed tax payable of $20,000 or more |
| 15 May 2027 | Remaining individuals and trusts lodging through a registered tax agent |
| 5 June 2027 | Concessional date for returns otherwise due 15 May, where any payment is also made by this date |
Note on super: quarterly super guarantee due dates ended on 30 June 2026. Under Payday Super, which started on 1 July 2026, contributions must reach your employees’ super funds within seven business days of each payday. There is no longer a 28 October quarterly super deadline to plan around. If you employ staff, this is the single biggest change to your compliance calendar this year, and our payroll services team can confirm your pay cycle is set up correctly.
When is the tax return deadline in Australia?
The income year runs from 1 July to 30 June. For the year ending 30 June 2026, a return lodged by the taxpayer directly is due by 31 October 2026. Several of the dates in the table above fall on a weekend, including 31 October 2026 and 15 May 2027. Where a due date lands on a weekend or public holiday, lodgement or payment on the next business day is treated as being on time, but it is not a reason to plan for the later day.
The deadline is not fixed at one date for everyone. Lodgement history, the size of your last tax bill, whether you are a new registrant, and whether you use an agent all move the actual due date. That is why two people in the same street can have due dates seven months apart and both be correct.
The 31 October rule most people miss
Signing up with a tax agent after 31 October does not restore the extended deadline. You must already be on a registered agent’s client list before that date for the later date to apply to you. Every year we see people start looking for an accountant in the last week of October, only to find the window has closed and their return is already tracking late.
Practical rule: if you think you will need extra time, get on an agent’s books in September or early October. The registration takes minutes; the extension it protects is worth months.
Do self-lodgers and tax agent clients have the same deadline?
No. Self-lodgers work to 31 October with no flexibility built in. Agent clients are allocated a date under the ATO’s lodgement program, which depends on their circumstances.
| Who you are | Typical due date |
|---|---|
| Lodging your own return | 31 October 2026 |
| Agent client, prior-year return outstanding | 31 October 2026 |
| Agent client, last return had tax payable of $20,000 or more | 31 March 2027 |
| All other agent clients | 15 May 2027, with a concession to 5 June 2027 |
What if prior-year returns are outstanding?
If you had one or more prior-year returns outstanding as at 30 June 2026, your 2025-26 return is due 31 October 2026 regardless of whether an agent handles your affairs. Being behind removes the concession rather than extending it. Clearing the backlog first is usually the fastest way to restore access to the later dates in future years.
What happens if you miss the ATO tax return deadline?
The failure to lodge on time penalty is charged in fixed units rather than as a percentage. One penalty unit applies for each 28-day period, or part of a period, that the return is overdue, up to a maximum of five units.
The Commonwealth penalty unit rose to $364 on 1 July 2026, up from $330. For a small entity that puts the maximum failure to lodge penalty at $1,820 for a single return. Medium and large entities are charged multiples of that base amount, so the exposure scales quickly for bigger businesses with several obligations running late at once.
Separately, the general interest charge applies to any tax debt left unpaid after its due date, and it compounds daily. There is a sting in this that many people have not caught up with: general interest charge and shortfall interest charge incurred on or after 1 July 2025 are no longer tax deductible. Interest on an ATO debt used to soften itself at tax time. It no longer does, which makes carrying a balance materially more expensive than it was two years ago.
One point worth separating: the failure to lodge penalty attaches to the lodgement, not the payment. If you cannot pay the bill, lodge anyway. Lodging on time and arranging terms is a far better position than staying silent and accruing both a penalty and non-deductible interest.
How to prepare and lodge before the deadline
Delays are almost always caused by missing paperwork rather than by the lodgement process itself. Most income statements, bank interest and dividend data pre-fill into myGov by late July, but self-employed income, rental income and work-related deductions still have to be assembled by you.
Reviewing last year’s notice of assessment before you start is a simple check that no recurring income source or deduction has been left off. If you own an investment property, our property accounting team can tell you which records to keep through the year rather than reconstructing them in October.
What records should small business owners prepare?
Organise income records, expense receipts, and vehicle or asset logs ahead of the deadline. Keep your BAS and GST obligations separate in your own head from the annual return, because they run on their own reporting cycle with their own dates. A running expense log kept through the year, rather than rebuilt at deadline time, cuts both preparation cost and the risk of missed deductions.
Does every sole trader need to lodge, regardless of income?
Yes. If you carried on a business at any point during the year you must lodge a return, even if you earned nothing. There is no tax-free threshold that excuses a business from lodging, and that catches out a lot of people in their first year of trading. Our sole trader accounting service covers this from the first return onwards.
Common questions
Does the deadline apply to paying tax as well as lodging it?
Not necessarily. Lodgement and payment dates can fall on different days, so check both. For agent-lodged returns due 15 May, payment is generally due 21 days after the lodgement due date or after you receive your notice of assessment, whichever is later.
What should I do if I have already missed the deadline?
Contact the ATO or your agent rather than waiting for a notice. Prompt contact often opens the door to penalty remission or a payment arrangement, particularly where your lodgement history is otherwise clean. A registered tax agent can make that request on your behalf.
Do I need to apply for the 5 June concession?
No. Where it applies it is automatic, provided any payment owing is also made by 5 June.
I have several years outstanding. Where do I start?
With the oldest year. Returns are generally assessed in sequence, and clearing the backlog is what restores your access to the extended lodgement dates. See our individual tax return service for how we work through multiple years at once.
Get ahead of 31 October
The date that matters most is not the one you lodge by. It is 31 October, the day the door closes on getting a later deadline at all. If you are not already on an agent’s client list, that is the action worth taking this month.
Talk to specialist before it costs you
15-minute discovery call. No obligation, no jargon.
Book your free 15 minute consultation with Nanak Accountants & Associates on 1300 626 258, and we will confirm which lodgement date actually applies to you before it becomes a problem.
This article provides general information only for Australia. It does not consider your objectives, financial situation or needs. Tax rules depend on individual circumstances and can change. Check current ATO guidance and seek professional advice before acting. Nanak Accountants & Associates, Registered Tax Agent 26113345.
