Disclaimer: ATO lodgement dates, penalty amounts, and agent extension programs can change. Always verify current due dates and penalty unit values at ato.gov.au before relying on this article. This is general guidance only, not tax advice.
A BAS lodgement checklist is the set of steps a bookkeeper or BAS agent completes before submitting a Business Activity Statement to the ATO — and the calendar of due dates that governs when each submission must land. For practices managing a large client portfolio, missing a single deadline triggers an automatic penalty. Knowing every date in advance, and reconciling throughout the quarter rather than scrambling at the end, is the difference between a calm lodgement season and a costly one.
This article gives you every 2026 BAS due date in one place, explains the agent extension program, outlines current penalty exposure, and ends with a six-item pre-lodgement checklist your team can run in under an hour.
Standard quarterly BAS lodgement dates for 2026
Most Australian businesses lodging GST quarterly follow a fiscal year aligned with the July–June tax year. According to the ATO for the 2025–26 financial year, the four quarters and their standard due dates are:
| Quarter | Period covered | Standard due date |
|---|---|---|
| Q1 | 1 July – 30 September 2025 | 28 October 2025 |
| Q2 | 1 October – 31 December 2025 | 28 February 2026 |
| Q3 | 1 January – 31 March 2026 | 28 April 2026 |
| Q4 | 1 April – 30 June 2026 | 28 July 2026 |
Weekend and public holiday rule: If a due date falls on a Saturday, Sunday, or national public holiday, the ATO moves the deadline to the next business day. State-specific public holidays can also shift deadlines for businesses in those states. Confirm each date against current ATO guidance, as the ATO publishes an updated lodgement due-date tool on its website each year.
Monthly GST lodgement dates for 2026
Businesses with an annual GST turnover exceeding $20 million are required to lodge and pay GST monthly. Businesses below that threshold can also elect to lodge monthly. For monthly lodgers, the standard due date is the 21st of the month following the reporting period.
| Reporting month | Due date |
|---|---|
| January 2026 | 21 February 2026 |
| February 2026 | 21 March 2026 |
| March 2026 | 21 April 2026 |
| April 2026 | 21 May 2026 |
| May 2026 | 21 June 2026 |
| June 2026 | 21 July 2026 |
| July 2026 | 21 August 2026 |
| August 2026 | 21 September 2026 |
| September 2026 | 21 October 2026 |
| October 2026 | 21 November 2026 |
| November 2026 | 21 December 2026 |
| December 2026 | 21 January 2027 |
As with quarterly dates, if the 21st falls on a weekend or public holiday the deadline moves to the next business day.
BAS agents and the lodgement extension program
Registered BAS agents and tax agents operate under the ATO's Registered Agent Lodgement Program, which grants extended deadlines on behalf of their clients. These extensions typically add approximately four weeks to the standard due date, allowing practices to spread their workload across a longer window.
The exact extension dates vary from year to year and are published by the ATO at the start of each financial year. Practices should log in to the ATO's Online Services for Agents portal to download the current lodgement program schedule and confirm the specific extended dates applicable to their client list.
Key points about the agent extension program:
- Extensions apply per client, not per practice. A client lodged through a registered agent receives the extended date; a client who lodges directly does not.
- The extension does not apply if the BAS was already overdue when the client engaged the agent.
- Agents who fail to meet their own lodgement programs can have the program suspended, reverting affected clients to standard due dates.
For current agent due dates, refer directly to ato.gov.au.
Penalties for late BAS lodgement
The ATO's failure-to-lodge (FTL) penalty applies automatically when a BAS is not lodged by its due date. The penalty is calculated in penalty units, which the government adjusts periodically.
As of 2026, one penalty unit is $330. The FTL penalty accumulates at one penalty unit per 28-day period the BAS remains overdue, up to a maximum based on entity size:
| Entity type | Maximum FTL penalty | Equivalent penalty units |
|---|---|---|
| Small entity | $660 | 2 units |
| Medium entity | $1,650 | 5 units |
| Significant entity | $1,650 (base) | 5 units (can be higher) |
The ATO classifies entity size by tax turnover. Small entities are generally those with under $1 million in annual turnover.
Penalty remission: The ATO has discretion to remit FTL penalties for entities with a strong prior compliance record, particularly for a first or second late lodgement. Remission is not automatic — the practice or client must request it, and the ATO will consider the overall compliance history. Penalties for entities with a pattern of late lodgement are unlikely to be remitted.
Penalty unit values are set by the Crimes Act 1914 (Cth) and can change with each federal budget. Verify the current value at ato.gov.au before using any penalty figures for client advice.
BAS lodgement pre-lodgement checklist
A structured BAS lodgement checklist prevents the last-minute errors that cause amended lodgements and penalty exposure. Run these six steps before submitting any BAS:
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Bank reconciliation complete — every bank and credit card account must be fully reconciled to the statement balance for the last day of the reporting period. Unreconciled transactions distort both G1 and 1B. If transactions are still sitting in the review queue, the BAS is not ready.
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Review queue cleared — all transactions flagged for manual review must be coded or excluded before GST totals are extracted. A large review queue at lodgement time is a sign that the reconciliation was not maintained throughout the quarter — see our BAS preparation guide for how to keep the queue near zero.
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GST code distribution checked — run a GST code summary report and confirm the distribution of GST, GST-free, and input-taxed codes is consistent with prior quarters. An unexpected spike in GST-free or BAS-excluded lines warrants investigation before lodgement.
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G1 vs ledger cross-check — the G1 total (total sales) must reconcile to the income lines in the profit and loss for the period. Any discrepancy needs a written explanation before the BAS is submitted.
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W1 vs STP cross-check — for entities with employees, the W1 (gross wages) figure on the BAS must be consistent with the Single Touch Payroll data reported to the ATO for the same period. A mismatch between W1 and STP data is a common audit trigger.
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1B reasonableness check — the 1B (GST on purchases) figure should sit within an expected range relative to G1 and the business's known input-taxed or GST-free purchase mix. An unusually high 1B compared to prior periods may indicate double-coded transactions or a miscategorised capital purchase.
For a detailed version of this workflow, see our BAS preparation checklist for accounting practices.
Getting ready well before the deadline
The practices that handle lodgement season without stress are the ones that reconcile continuously, not the ones that catch up at quarter end. With transactions auto-coded throughout the quarter, running through the six checklist items above takes 20 to 45 minutes per client. Practices that leave bank reconciliation until the week before the due date are effectively compressing four months of data entry into a few days — and that is where coding errors, missed items, and amended lodgements come from.
The practical approach is to set a practice-level internal deadline two weeks before the ATO due date. That buffer absorbs client delays, missing bank statements, and any items that need a client conversation before the GST code can be confirmed. When the ATO due date arrives, the BAS should already be reviewed and waiting for final sign-off.
For practices using Reconlink, the auto-coding engine processes transactions as you import bank statements (CSV, Excel or PDF) — or forward them to a per-client email inbox — so by the time the quarter closes the review queue is typically under ten items per client. Explore Reconlink's features to see how continuous reconciliation changes the lodgement workflow.
Frequently asked questions
What happens if I miss a BAS lodgement date?
The ATO automatically applies a failure-to-lodge penalty starting from the day after the due date. The penalty accrues in 28-day blocks at one penalty unit ($330 as of 2026) per block, up to the cap for your entity size. You can request penalty remission if you have a strong compliance history, but the request is not guaranteed to succeed. Lodge as soon as possible to stop the penalty clock.
Do I get extra time if I lodge through a BAS agent?
Yes. Registered BAS agents and tax agents operating under the ATO's Registered Agent Lodgement Program receive extended due dates for their clients. The extensions are typically around four weeks beyond the standard dates, but exact dates vary each year. Your practice should confirm current agent due dates through the ATO's Online Services for Agents portal.
How do I know if my business should lodge monthly or quarterly?
Businesses with annual GST turnover above $20 million must lodge monthly. Businesses below this threshold default to quarterly lodgement but can elect to lodge monthly if it suits their cash flow. Contact your registered BAS agent or check the ATO's website to confirm which reporting cycle applies to each client.
Can I change my BAS lodgement frequency?
Yes, in most cases. Businesses can apply to change from quarterly to monthly lodgement, or vice versa. Changes generally take effect from the start of the next tax period. Contact the ATO directly or work through a registered agent to make the change.
What is the fastest way to prepare a BAS close to the deadline?
The fastest preparation happens when the bank reconciliation is already current. If you are two weeks out from the due date and the accounts are fully reconciled, the BAS preparation workflow described in this article takes under an hour. If the accounts are not reconciled, the bottleneck is not the BAS form — it is the transaction coding. Start there, and consider a reconciliation tool that auto-codes common transactions to reduce the manual workload in future quarters.
Lodgement deadlines are fixed. The only variable your practice controls is how much work is done before they arrive. Start reconciling before lodgement season to make every BAS due date a non-event.