Your 2026 Tax Return in Adelaide: What’s Changed and Why 31 October Matters

Every year around this time the same conversation happens in our Adelaide office. Someone calls in early October, slightly sheepish, and asks whether they have missed the boat. Usually they have not — but the answer depends entirely on one thing most people get wrong about the 31 October deadline.

This year the stakes are a little higher than usual. The 2025-26 return is the last one prepared under the old work-related expense rules, the first one where the Australian Taxation Office’s own interest charges are no longer deductible, and the one that sets your starting position for a run of tax changes that begin on 1 July 2026 and keep going through to 2027-28.

Here is what Adelaide taxpayers need to know before the end of October, and what to do about it.

The 31 October deadline is not what most people think it is

If you lodge your own return, the due date for the year ended 30 June 2026 is 31 October 2026. That applies whether you are in Adelaide, Adelaide’s suburbs or anywhere else in the country. That date falls on a Saturday this year, and the ATO’s standing practice is that where a due date falls on a weekend or public holiday you can lodge or pay on the next business day — so in practice you have until Monday 2 November 2026.

If you use a registered tax agent, the picture is completely different. Most individual clients of a tax agent do not lodge until 15 May 2027, and payment is not due until well after that. The catch — and this is the part that trips people up — is that you have to be on the agent’s client list by 31 October to get the extension. Engaging an Adelaide accountant on 14 November does not retrospectively buy you six extra months. It buys you a late return.

So if you have been meaning to move from doing it yourself in myTax to having it done properly, or you are switching from your old accountant, the practical deadline is the same 31 October date. Make the call in October, not in December.

The agent lodgment program itself has tiers, and not everyone lands on 15 May:

• 31 October 2026 — if you had any prior year returns outstanding as at 30 June 2026, or you have previously been prosecuted for non-lodgment. Fall behind once and you lose the concession entirely until you are current again.
• 31 March 2027 — if your most recent return showed a tax liability of $20,000 or more.
• 15 May 2027 — everyone else, with a further concession allowing lodgment by 5 June without penalty provided any payment is made by the same date.

Payment dates for the 15 May group are staggered according to when you actually lodge: lodge by 12 February 2027 and payment is due 21 March 2027; lodge between 13 February and 12 March and it is due 21 April 2027; lodge from 13 March onwards and it is due 5 June 2027. Lodging early does not mean paying early in any meaningful sense, but it does mean you know the number months in advance — which matters if you are budgeting for it.

What being late actually costs

The failure to lodge on time penalty is one penalty unit for each 28 days (or part of a period of 28 days) that the return is overdue, capped at five penalty units for an individual. The penalty unit rate is $364 from 1 July 2026, so a return that is more than four months late attracts the full $1,820.

The larger cost is usually the interest. General interest charge accrues on unpaid tax, and from 1 July 2025 the general interest charge and shortfall interest charge are no longer tax deductible. That change bites for the first time in the 2025-26 return you are lodging right now. Under the old rules an interest charge cost you roughly half its face value after the deduction. It now costs you all of it. For Adelaide small business owners carrying an ATO payment plan, this is a genuine change in the economics of using the ATO as a lender, and it is worth revisiting how that debt is funded.

What has actually changed in the 2025-26 return

Less than the headlines suggest, but the changes that are there matter.

ATO interest is no longer deductible. As above — general interest charge and shortfall interest charge incurred from 1 July 2025 cannot be claimed.

The $2 minimum for gifts and donations is gone. Deductible gifts to deductible gift recipients are now claimable regardless of amount. Small, but it tidies up a lot of $1 round-up donations at the supermarket checkout.

Rental property guidance has been rewritten. The ATO issued Taxation Ruling TR 2026/1 along with two practical compliance guidelines, PCG 2026/2 and PCG 2026/3, covering rental income, rental expenses and holiday home deductions. If you own a rental in Adelaide or a shack at Victor Harbor, Normanville or on Yorke Peninsula, the holiday home guidance in particular is worth a look — apportionment of expenses where a property is genuinely available for rent for only part of the year is a long-running area of dispute, and there is now clearer guidance on what the ATO expects.

Contractor payments are now pre-filled. Around $21 billion in payments to contractors reported through the taxable payments annual report now flow into pre-filled returns automatically, covering construction, cleaning, courier, IT and security work. If you are a sole trader in any of those industries — and Adelaide’s building trades are heavily represented — the income the ATO already knows about will appear in your return. Businesses have until 28 August to lodge their taxable payments annual report, so returns lodged before that date may be missing data.

What has not changed, despite what you may have read

There has been a lot of coverage of the government’s tax reform package, and it has left plenty of people expecting relief in a return where it simply does not apply yet. None of the following affect the 2025-26 return:

• The $1,000 instant deduction for work-related expenses — starts 2026-27.
• The Working Australians Tax Offset — starts 1 July 2027.
• The capital gains tax changes and the negative gearing restrictions — both start 1 July 2027.
• Changes to the private health insurance rebate.

For the 2025-26 return, the ordinary rules apply: substantiate everything, keep your receipts, and claim what you actually spent.

The numbers that apply to your 2025-26 Adelaide tax return

Resident individual rates for the year ended 30 June 2026, before the Medicare levy:

• $0 – $18,200: nil
• $18,201 – $45,000: 16c for each $1 over $18,200
• $45,001 – $135,000: $4,288 plus 30c for each $1 over $45,000
• $135,001 – $190,000: $31,288 plus 37c for each $1 over $135,000
• $190,001 and over: $51,638 plus 45c for each $1 over $190,000

Working from home. The fixed rate method is 70 cents per hour worked from home for 2025-26. It covers electricity and gas, home and mobile internet, home and mobile phone, and stationery and computer consumables — you cannot claim any of those separately on top. You can still separately claim the decline in value of a desk, chair or laptop. The record-keeping requirement is the one that catches people: you need a record of the actual hours worked from home across the whole year, contemporaneously kept. An estimate, or a four-week diary extrapolated across twelve months, is not accepted. You also need at least one bill for each expense category the rate covers.

Medicare levy surcharge. If you did not hold an appropriate level of private hospital cover, the surcharge applies once income for surcharge purposes exceeds $101,000 for a single or $202,000 for a family. Singles pay 1% from $101,001, 1.25% from $118,001 and 1.5% from $158,001. Families pay the same rates from $202,001, $236,001 and $316,001, with the family threshold lifted by $1,500 for each dependent child after the first. For an Adelaide professional couple, crossing a threshold by a few hundred dollars can cost more than the hospital cover would have.

Superannuation. The concessional contributions cap for 2025-26 was $30,000, rising to $32,500 for 2026-27. If your total superannuation balance was under $500,000 at 30 June 2025 you may be able to use unused cap from earlier years under the carry-forward rules — which is one of the few genuinely useful things you can still do after year end, since a personal deductible contribution for 2025-26 had to be made by 30 June 2026 but the deduction notice and the return itself are still in play.

Where Adelaide taxpayers most often get it wrong

Rental properties are the standout. The ATO has said that nine out of ten returns reporting rental income and deductions contain at least one error. The recurring problems are not exotic — claiming the full interest deduction on a loan that was partly redrawn for private purposes, claiming capital improvements as repairs, missing income from short-stay platforms, and claiming a full year of expenses on a property that was only genuinely available for rent for part of it.

Work-from-home claims are the second. Adelaide has a high proportion of hybrid workers in health, education and professional services, and the 70 cents per hour method is simple enough that people assume the substantiation is too. It is not — the full-year hours record is a hard requirement, and it is exactly what the ATO asks for first.

Then there are the smaller ones: laundry claims that assume $150 is an automatic entitlement rather than a substantiation threshold, self-education claims for study that is not sufficiently connected to current work, and the general belief that $300 of work expenses can be claimed without spending anything. The $300 figure is a limit on when you need written evidence, not a free allowance — you still have to have incurred the expense and be able to show how you worked out the claim.

Why this return matters more than usual

From 1 July 2026 the lowest marginal rate falls from 16% to 15%, with a further legislated cut the following year. From 2026-27 there is a $1,000 instant deduction for work-related expenses available to residents earning labour income — you get it automatically, it is reduced by any actual work-related expenses you claim (union fees and professional association memberships excepted), and around 6.2 million workers are expected to be better off by an average of about $205. From 1 July 2027 the Working Australians Tax Offset adds up to $250.

The practical consequence is that for a lot of Adelaide employees with modest deductions, 2025-26 is the last year where the effort of collecting receipts is what determines the refund. From next year, if your genuine work-related expenses come in under $1,000, you get the $1,000 anyway.

That is not a reason to relax this year. It is a reason to get 2025-26 right — because a clean, correctly substantiated return is what keeps you inside the tax agent lodgment program, and because the 2027 changes to negative gearing and capital gains tax will be assessed against a starting position that your current returns help establish. Property investors in particular should be gathering ownership and cost base records now rather than in June 2027.

What to do before 31 October

1. If you are not already with a tax agent, engage one this month. That single step moves your deadline from 31 October 2026 to as late as 15 May 2027 — but only if it happens before 31 October.
2. Check for outstanding prior year returns. If anything was unlodged at 30 June 2026, your due date is 31 October regardless of who prepares it. Getting current is the first job.
3. Wait for pre-fill to settle if you have contractor or investment income. Taxable payments annual reports were due 28 August, and managed fund and share registry data lands progressively. Lodging too early is a common cause of amendments.
4. Pull together your work-from-home hours record before you look for anything else. If it does not exist for the full year, you need the actual cost method, and that is a different conversation.
5. For rental properties, get the loan statements, not just the agent summary. Redraw and offset arrangements are where the interest deduction goes wrong.
6. If you are likely to owe money, lodge anyway. Lodgment and payment are separate obligations. Lodging on time and arranging a payment plan avoids the failure to lodge penalty entirely — and now that ATO interest is not deductible, knowing the number early is worth more than it used to be.

Getting help in Adelaide

Most people do not need a complicated return. They need one that is correct, lodged on time, and prepared by someone who has looked at the whole picture rather than just typing in the pre-fill. If you have a rental, a family trust, a business, an SMSF, or you are a medical professional with multiple income sources, the return is where several years of planning either shows up or does not.

We have written separately about what an accountant costs in Adelaide, about choosing a business structure, and about South Australian land tax for property investors and trusts.

If you would like your 2026 return handled properly — or you simply want to be on a lodgment program before the end of October — get in touch. Our tax team works with individuals, families and business owners across Adelaide and regional South Australia.

This article provides general information only and does not take into account your personal circumstances. Rates, thresholds and due dates are current as at September 2026 and are subject to change. You should seek advice tailored to your situation before acting on anything above.