When Is Your BAS Due in 2026–27? Q1 Deadline Is 28 October (And What It Really Costs to Miss It)
If you're a sole trader, contractor, or gig economy earner registered for GST, your first Business Activity Statement for the 2026–27 financial year is due on 28 October 2026. That's the same week as the 31 October deadline most people associate with their personal tax return — and mixing the two up is one of the most common (and costly) mistakes we see at this time of year.
This guide walks through exactly when your BAS is due this quarter, what counts as being "on time" if you lodge through a registered BAS agent, what the ATO actually charges you if you're late (both for lodging and for paying), and how gig economy earners — think Uber, DiDi, Uber Eats, DoorDash, Menulog and Airbnb hosts — figure out whether they need to be doing this at all.
Quick answer: if you report GST quarterly, your Q1 2026–27 BAS (covering July, August and September 2026) is due 28 October 2026. If a registered BAS agent lodges for you, you may get extra time — though not for every quarter. Miss the deadline and you're generally looking at a failure to lodge penalty of one penalty unit ($364) for every 28 days it's overdue, up to five units, plus general interest charge on any unpaid amount.
What This Guide Covers
When Is Your Q1 BAS Due for 2026–27?
For most GST-registered sole traders and small businesses reporting quarterly, the due date for your Business Activity Statement covering 1 July to 30 September 2026 — your Q1 BAS for the 2026–27 financial year — is 28 October 2026, according to the ATO's official BAS due dates page (last updated 17 September 2026).
That date applies whether you're lodging and paying at the same time, which is how most sole traders do it — you don't get a separate deadline for lodging versus paying your quarterly BAS.
If you use a registered tax or BAS agent, you may be entitled to a later due date under the ATO's lodgment program concessions for 2026–27. Worth knowing: that concession generally doesn't apply to your Q2 (October–December) BAS, because its standard 28 February due date already bakes in an extra month compared with the usual 28-day pattern. Ask your agent directly which quarters they can extend for you — it varies.
Don't Confuse This With Your 31 October Tax Return
Deadline
Here's where a lot of people trip up, and it's exactly the kind of timing mix-up we want this guide to prevent. Two completely different obligations land within days of each other every October:
• 28 October 2026 — Q1 BAS due (GST, PAYG withholding, PAYG instalments for the quarter)
• 31 October 2026 — the standard self-lodgment deadline for your 2025–26 individual
income tax return, if you're not using a registered tax agent.
These are not the same thing, they don't cover the same period, and paying attention to one doesn't get you out of the other. Your BAS reports GST and other obligations for the quarter you just finished (July–September 2026, which falls in the 2026–27 financial year). Your tax return, lodged around the same time, reports your income and deductions for the financial year that just ended (2025–26). If you're a sole trader registered for GST, you'll typically be doing both — and if you use a registered tax agent for your income tax return, remember that doesn't automatically extend your BAS deadline, since BAS extensions come from a registered BAS agent (who may or may not be the same person). For more on what happens if you miss the income tax deadline specifically, see our guide to the 2026 tax return deadline and late lodgment penalties.
The Full 2026–27 BAS Quarterly Calendar
If you report GST quarterly, here's the complete run of due dates for the 2026–27 financial year, per the ATO:
• Quarter 1 (July–September 2026): due 28 October 2026
• Quarter 2 (October–December 2026): due 28 February 2027
• Quarter 3 (January–March 2027): due 28 April 2027
• Quarter 4 (April–June 2027): due 28 July 2027
If you report monthly instead — which is compulsory once your GST turnover reaches $20 million, and optional for some smaller businesses — your BAS is due on the 21st of the following month, every month, all year round.
Save these four quarterly dates somewhere you'll actually see them. A surprising number of the late-lodgment cases we deal with aren't because someone didn't have the money or the numbers ready — they simply lost track of the date.
Do You Actually Need to Lodge a BAS?
You only need to lodge a BAS if you're registered for GST. Whether you need to register comes down to your GST turnover, with one important exception for a specific group of gig economy earners. Per the ATO's guide to registering for GST (last updated 14 September 2026):
• General threshold: you must register for GST once your current or projected GST turnover reaches $75,000 in a 12-month period ($150,000 for non-profit organisations).
• You have 21 days from when you realise you'll go over the threshold to register.
• Ride-sourcing drivers are the exception: if you drive for Uber, DiDi, Ola or any similar ride-sourcing platform operating in Australia, you must register for GST from the very first dollar you earn — the $75,000 threshold doesn't apply to you at all.
That last point catches a lot of people out. Someone driving for a rideshare platform a few hours a week, earning well under $75,000 a year, often assumes they're under the radar for GST. They're not — ride-sourcing is treated as taxi travel for GST purposes, and registration is compulsory regardless of turnover.
Food delivery work (Uber Eats, DoorDash, Menulog) and Airbnb-style short-term rental income are treated differently: both count toward the standard $75,000 threshold like any other business income, rather than triggering compulsory registration on their own. If you're combining delivery driving with a full-time job, or running an Airbnb alongside other freelance income, add all your GST-turnover-relevant income together when working out whether you're near the threshold — it's your total turnover across activities that matters, not each income stream in isolation.
If none of this applies to you — you're not GST-registered and your turnover is comfortably under $75,000 — you don't need to lodge a BAS at all. For a broader look at when and how to register, see our full guide to Australia's GST registration thresholds and compliance.
Monthly, Quarterly or Annual? Choosing Your GST Reporting Cycle
Most small sole traders default to quarterly reporting, but you do have some choice:
• Quarterly (the default for most small businesses): four BAS lodgments a year, on the dates above.
• Monthly: compulsory once your GST turnover hits $20 million; optional below that if you'd rather manage GST in smaller, more frequent chunks (some businesses prefer this for cash flow visibility).
• Annually: available if you're voluntarily registered for GST with turnover under $75,000, or in a small number of other specific circumstances the ATO sets out — this isn't available to most actively trading sole traders once they're over the compulsory registration threshold.
If you're a new sole trader trying to decide, quarterly is usually the practical middle ground — frequent enough that GST doesn't pile up into a shock bill, infrequent enough that it's not a monthly chore.
What a Late BAS Actually Costs You (Failure to Lodge Penalty)
If you don't lodge your BAS by 28 October and you don't have a registered agent extension, the ATO can apply a Failure to Lodge (FTL) on time penalty. Here's how it's actually calculated, per the ATO's failure to lodge on time penalty page (last updated 22 June 2026):
• For individuals and small withholders/entities, the penalty is one penalty unit for every 28 days (or part thereof) your BAS is overdue, up to a maximum of five penalty units.
• As of 1 July 2026, a penalty unit is worth $364 (up from $330 the year before), based on the ATO's penalty units page.
• That means the maximum FTL penalty for a small entity lodging a single BAS very late is currently $1,820 (5 × $364) — and that's before any interest on unpaid amounts.
Worked example: say your Q1 BAS was due 28 October 2026 and you finally lodge it on 20 December 2026 — 53 days late. That's within the second 28-day block (29 to 56 days overdue), so you'd be up for 2 penalty units: 2 × $364 = $728. Lodge it even later, in the fourth or fifth 28-day block, and you're looking at $1,092 to $1,456 — purely for lodging late, regardless of whether you owed any GST at all.
Larger businesses (medium and large withholders, significant global entities) face multipliers of 2x, 5x or 500x on this base penalty — but for the sole traders and gig workers this guide is written for, the "up to 5 units" calculation above is what applies.
One thing worth knowing: the ATO doesn't automatically apply the maximum penalty, and remission (having the penalty reduced or cancelled) is possible if you have a reasonable excuse or a clean lodgment history — but you have to ask, and it's not guaranteed.
What Happens If You Pay Late (General Interest Charge)
The FTL penalty is for lodging late. If you lodge on time but don't pay the GST or other amounts you owe by the due date, a separate charge applies: the General Interest Charge (GIC), calculated daily on the outstanding balance. Per the ATO's GIC rates page (last updated 4 September 2026):
• The GIC annual rate for July–September 2026 is 11.43%.
• The GIC annual rate for October–December 2026 is 11.51%.
• Rates are reset every quarter, so if your debt carries over multiple quarters, check the current rate rather than assuming it stays the same.
Worked example: if you owe $3,000 in GST from your Q1 BAS and pay it 30 days late during the October–December quarter (11.51% p.a.), that's roughly $3,000 × 11.51% ÷ 365 × 30 ≈ $95 in GIC on top of what you already owed — and it keeps accruing daily until you pay in full.
An important, easy-to-miss detail: since 1 July 2025, GIC and the related Shortfall Interest Charge (SIC) are no longer tax deductible. Before that date, businesses could at least claim a deduction for ATO interest charges, softening the blow slightly. That's no longer the case — a late payment now costs you the full GIC amount with no offsetting deduction, which makes paying on time (or at least lodging on time and setting up a payment plan) noticeably more valuable than it used to be.
Worked Example: A Rideshare Driver's Q1 BAS
To make this concrete, here's a simplified example. Say you drive for a rideshare platform in Brisbane, alongside a part-time job, and for July–September 2026 you earned $9,000 in gross rideshare fares.
Because ride-sourcing drivers must be GST-registered regardless of turnover, that $9,000 includes GST. Working backwards, your GST liability on fares is roughly $9,000 ÷ 11 ≈ $818. Against that, you can claim GST credits on eligible business expenses for the same quarter — say $200 in fuel, a portion of your phone plan, and rideshare platform fees, totalling around $1,100 of GST-inclusive expenses, giving you roughly $100 in GST credits.
Net GST payable for the quarter: approximately $818 − $100 = $718, reported and paid with your Q1 BAS by 28 October 2026. This is a simplified illustration — your actual apportionment between business and private use, and what you can claim, depends on your specific records and circumstances, which is exactly the kind of thing worth checking with a registered agent before you lodge.
Should You Lodge This Yourself, or Have a Professional Handle It?
A Q1 BAS looks simple on paper — a handful of boxes — but getting those numbers right means correctly separating GST-inclusive income, working out exactly which expenses actually carry a claimable GST credit, and applying the right business-versus-private apportionment on things like a vehicle or phone plan. For gig economy earners juggling income from more than one platform, or anyone still new to being GST-registered, small errors here are easy to make — and they can mean an inflated or understated BAS, which either costs you unnecessarily or draws unwanted attention from the ATO.
Rather than risk that, most of the sole traders and gig workers we work with prefer to have it handled properly from the start. Baron Tax & Accounting looks after GST registration and ongoing BAS lodgment for clients across Australia — every quarter, on time, with the numbers checked properly before anything goes near the ATO. If you'd rather hand your Q1 BAS to us than work through it yourself, get in touch and we'll take care of it before 28 October.
For a fuller look at what actually goes on a BAS and where DIY lodgment most often goes wrong, see our guide to how BAS lodgment works in Australia.
Simpler BAS vs Full BAS
Most small businesses with GST turnover under $10 million use Simpler BAS reporting, which only requires you to report three GST figures: total sales (G1), GST on sales (1A), and GST on purchases (1B) — a meaningful reduction from the full BAS, which also asks for export sales, GST-free sales, capital purchases and non-capital purchases figures. If you're a sole trader or gig worker under that turnover threshold, you're almost certainly eligible for Simpler BAS, which is one less thing to worry about heading into 28 October.
Your Pre-28-October Checklist
• Confirm you're actually required to lodge — check your GST registration status and turnover against the thresholds above.
• Reconcile your July, August and September income and expenses, including any rideshare, delivery or short-term rental platform statements.
• Separate GST-inclusive figures correctly — don't accidentally report GST-inclusive income as though it were GST-exclusive.
• Gather GST credits you're entitled to claim on business expenses for the quarter.
• Check whether you're on Simpler BAS or full BAS reporting, so you know which figures you actually need.
• Decide whether you're lodging this one yourself or handing it to a registered BAS agent — don't leave that decision until 27 October.
• If you can't pay in full by the due date, lodge on time anyway and contact the ATO about a payment plan — this avoids the FTL penalty even if GIC still applies to the unpaid amount.
• If you use a BAS agent, confirm your specific lodgment date with them rather than assuming a blanket extension applies.
Frequently Asked Questions
What is the BAS due date for Q1 of the 2026–27 financial year?
28 October 2026, for GST-registered sole traders and businesses reporting quarterly, covering the July–September 2026 period.
Is the BAS deadline the same as the tax return deadline?
No. The 28 October BAS deadline covers your GST and other quarterly obligations for July–September 2026 (2026–27 financial year). The 31 October deadline is for lodging your individual income tax return for the 2025–26 financial year if you're self-lodging without a registered tax agent. They're separate obligations that happen to fall in the same week.
Do Uber and DiDi drivers have to register for GST even if they earn under $75,000?
Yes. Ride-sourcing drivers must register for GST from their first dollar of income, regardless of turnover — this is a specific ATO rule that overrides the usual $75,000 threshold.
What about Uber Eats or DoorDash delivery drivers — same rule?
No, food delivery is treated differently from ride-sourcing for GST purposes. Delivery income counts toward the standard $75,000 GST registration threshold rather than triggering compulsory registration on its own.
What happens if I lodge my BAS late?
You may be charged a Failure to Lodge penalty of one penalty unit ($364 as at 1 July 2026) for every 28 days it's overdue, up to a maximum of five units ($1,820), plus General Interest Charge on any unpaid amount.
Can I get an extension on my BAS due date?
Registered tax or BAS agents can sometimes lodge on your behalf under extended due dates as part of the ATO's lodgment program, though this doesn't apply uniformly to every quarter — Q2, for example, already includes a built-in extra month. Speak to your agent about which quarters they can extend.
I can't afford to pay my BAS by 28 October — what should I do?
Lodge it on time regardless. The Failure to Lodge penalty is for not lodging, not for not paying, so lodging on time and then arranging a payment plan with the ATO for the amount owed avoids that penalty, even though General Interest Charge will still apply to the unpaid balance.
Is interest on a late BAS payment tax deductible?
No. Since 1 July 2025, General Interest Charge and Shortfall Interest Charge are no longer deductible, so late payment costs you the full charge with no offsetting tax benefit.
Do I need to lodge a BAS if I'm not registered for GST?
No. BAS lodgment obligations only apply once you're registered for GST (or have other reporting obligations like PAYG withholding). If your turnover is under the threshold and you haven't registered, you don't need to lodge one.
What's the difference between Simpler BAS and full BAS reporting?
Simpler BAS, available to businesses with GST turnover under $10 million, only requires three GST figures (total sales, GST on sales, GST on purchases). Full BAS asks for additional figures like GST-free sales, export sales, and capital versus non-capital purchases.
Need a Hand With Your BAS or GST Registration?
If you're not sure whether you need to register for GST, or you'd rather have a registered agent handle your quarterly BAS from here on, Baron Tax & Accounting can help — from ABN and GST registration through to ongoing BAS lodgment and your annual tax return. You can start your online tax return, check our ABN / GST registration service, use our tax calculator, or see our fees and about us pages.
Reach us at 758 Underwood Road, Rochedale South QLD 4123, on +61 7 3706 3147 / 1300 087 213, or at info@baronaccounting.com, Monday to Friday 09:30–17:00.
Disclaimer
This article provides general information only and does not constitute personal tax or financial advice. It does not take into account your objectives, financial situation or needs. Tax rules change and apply differently to each person's circumstances. Before acting, please seek advice from a registered tax agent. Baron Tax & Accounting accepts no liability for any loss arising from reliance on this article. Source references: ATO (ato.gov.au) and other Australian government agencies, current as at the date of publication.
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