BAS Due 28 July: What Your Sydney Bookkeeper Should Have Done By Now

It is June. The Q4 BAS lands on 28 July. A decent Sydney bookkeeper has already reconciled most of the quarter and could lodge tomorrow if they had to. Barry, meanwhile, is still "tidying" April and has started replying to your emails with a single word: "noted."

Published: June 2026

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What actually happens on 28 July

Three things collide on the same date this year, which is why this quarter is the worst one to have a slow bookkeeper.

First, the April to June BAS is due 28 July 2026 if you lodge it yourself. If a registered agent lodges electronically on your behalf, the concession date is 25 August 2026, but only if you were on their lodgement list before the original due date. Joining an agent's books on 27 July does not buy you the extension.

Second, 28 July is also the due date for the final quarterly super payment in Australian history. From 1 July 2026, Payday Super replaces the quarterly cycle entirely and super must reach the fund within 7 business days of each payday. So your bookkeeper is closing out one system while standing up another, in the same month.

Third, STP finalisation for the 2025-26 year is due 14 July. Your team's income statements do not go "tax ready" in myGov until it is done, which means every employee who wants their refund early will be messaging you from 15 July onwards.

That is three hard deadlines inside 28 days. If your bookkeeper has not mentioned any of them yet, that tells you everything. Run the 13 signs your Sydney bookkeeper is Boring Barry checklist and see how many land.

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The checklist: what should already be done by mid June

A bookkeeper who is on top of your file does not start the BAS in the last week of July. The work is continuous. Here is where your file should sit right now.

Bank feeds reconciled to within the last fortnight. Not "to March". Not "mostly". If you open Xero and the reconcile screen shows three months of unmatched transactions, the BAS is going to be built on guesswork and so is every number you have looked at this quarter.

GST coding reviewed, not just imported. Bank rules are great until they confidently code an overseas software subscription as GST-inclusive and quietly inflate your credits. Someone with a working brain needs to scan the GST audit report before lodgement, every quarter. This is exactly the kind of thing that surfaces in a messy Xero file review.

PAYG withholding matched to payroll. W1 and W2 on the BAS should agree with what the payroll system actually reported through STP for the quarter. If they have never been reconciled against each other, discrepancies compound until the ATO asks the question for you.

A draft GST position with a payment estimate. You should know roughly what the BAS will cost you weeks before it is due, so the cash is parked and ready. Finding out the number on lodgement day is not a cash flow strategy, it is a jump scare.

A plan for Payday Super. If your super still runs through the Small Business Superannuation Clearing House, you have a problem: the SBSCH closed to users from 1 July 2026. Payroll software or a commercial clearing house needs to be set up and tested before your first July pay run, not after.

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What late actually costs

The ATO's failure to lodge penalty is one penalty unit, currently $330, for every 28 days (or part thereof) the BAS is overdue, capped at five units. For a small entity that is up to $1,650 per late statement. Turn over more than $1 million and the penalty doubles.

Then there is the general interest charge on any unpaid amount, which compounds daily and is sitting above 10% per annum. Since 1 July 2025 that interest is no longer tax deductible, so the real cost is higher than the headline rate. The ATO generally gives a warning before penalising a first offence, but a pattern of late lodgement burns that goodwill fast, and it also torpedoes you if you ever need a payment plan or a remission request.

One more quiet cost: GST credits do not live forever. Leave old periods unlodged long enough and credits can expire, which is money you were owed simply evaporating because nobody pressed the button.

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"But my bookkeeper says they're on it"

Maybe they are. Here is a 60 second test. Ask them, today, for two things: the current reconciliation status of your bank accounts, and a draft GST estimate for the quarter. A good bookkeeper answers within a business day because the file is current and the answer is sitting right there. If the reply is a paragraph about how busy EOFY is, followed by silence, you have your answer, and you might also want to read what to do when your bookkeeper ghosts you.

The fee conversation matters here too. If you are paying by the hour, a late, panicked, last-week BAS costs you more than a calm one, because urgency bills beautifully. It is one of the structural reasons fixed monthly pricing exists, and one of the things covered in what a Sydney bookkeeper should cost in 2026.

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If you are behind right now

No shame, plenty of Sydney businesses are. The order of operations:

1. Lodge something. The penalty regime punishes silence, not honesty. If cash is tight, lodge on time and arrange a payment plan for the liability. A lodged BAS with a payment plan is a completely different conversation with the ATO than an unlodged one.
2. Get the file reconciled before anyone lodges. A BAS built on an unreconciled file is just a guess with a declaration attached.
3. Decide whether the person who let it get this far should be the one fixing it. Switching mid year is far less painful than people think, and the steps are laid out in how to change your Sydney bookkeeper without it getting weird.

If the file is genuinely cooked, a Free Xero Roast will tell you in plain English how bad it is and what it takes to fix, before you commit to anything.

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FAQ

When is the Q4 BAS due in 2026?

‍28 July 2026 if you lodge it yourself. If a registered agent lodges electronically and you were on their list before the due date, the concession date is 25 August 2026.

What is the penalty for lodging a BAS late?

‍One penalty unit ($330) per 28 day period or part thereof, up to five units, so a maximum of $1,650 for a small entity per statement. Entities with turnover between $1 million and $20 million face double that. Interest also accrues on unpaid amounts and is no longer tax deductible.

Do I still have to lodge a BAS if I had no activity?

‍Yes. A nil BAS still has to be lodged by the due date and can attract the same late penalties if it is not.

What is Payday Super and when does it start?

‍From 1 July 2026, employers must pay super at the same time as wages, with contributions reaching the fund within 7 business days of payday. The quarterly super cycle ends with the final payment due 28 July 2026.

When is STP finalisation due?

‍14 July 2026 for the 2025-26 financial year. Employees cannot lodge accurate tax returns until their income statements show as tax ready.

Can I switch bookkeepers right before a BAS deadline?

‍Yes, and it is more common than you would think. A competent new bookkeeper can take over a file, reconcile it, and lodge within days. You are owed your data and your Xero file regardless of who lodged last quarter.

My bookkeeper lodges through their agent, do I automatically get the 25 August date?

‍Only if the agent lodges electronically and you were on their lodgement program before the original due date. Confirm it in writing rather than assuming.

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About Sydney Bookkeeper

Sydney Bookkeeper is the modern, fixed-price Sydney bookkeeper for businesses with staff that are tired of slow, hourly, jargon-spouting incumbents. We work with professional services firms, construction and property businesses, agencies, tech and ecommerce companies, hospitality groups, and health practices across Sydney. Monthly bookkeeping, BAS lodgement, payroll, and Xero file cleanups, all on fixed monthly pricing, no lock-in.

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The team uses a registered BAS Agent for all BAS and IAS lodgement services. Full registration details, agent particulars, and copies of the Tax Practitioners Board (TPB) Code of Professional Conduct, the TPB complaints process, and any conditions on the agent's registration are available on request by emailing [contact email]. This content is general information only, written for Australian small and mid-market businesses. It does not constitute tax, financial product, or legal advice and should not be relied on as such. Tax obligations depend on your individual circumstances. For advice specific to your business, contact the team directly or consult a registered tax agent or licensed financial adviser. Sydney Bookkeeper is not a licensed tax agent or licensed financial adviser. Information was current at the time of publication and may change without notice. We review and update guides periodically.

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Sources

• ATO, Failure to lodge on time penalty: https://www.ato.gov.au/individuals-and-families/paying-the-ato/interest-and-penalties/penalties/failure-to-lodge-on-time-penalty
• ATO, Penalty units: https://www.ato.gov.au/individuals-and-families/paying-the-ato/interest-and-penalties/penalties/penalty-units
• ATO, Payday Super: https://www.ato.gov.au/paydaysuper
• ATO, Single Touch Payroll end-of-year finalisation: https://www.ato.gov.au/businesses-and-organisations/hiring-and-paying-your-workers/single-touch-payroll

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