# Quarterly BAS: Q1 (Jul–Sep)

Country: Australia
When: 28 October each year (paper and self-lodgers). Tax agents typically get extension to 25 November. For 2026-27 the Q1 date is Wednesday 28 October 2026. Lodging online can earn an extra two weeks, and a registered tax or BAS agent lodging for the client has the agent concession date of 25 November 2026. Monthly BAS lodgers file by the 21st of the following month, and GST turnover of A$20 million or more must lodge monthly.

Business Activity Statement covering July to September. Reports GST, PAYG withholding, PAYG instalments and FBT instalments for the quarter. Filed via myGov, ATO Online or accounting software. The later quarter dates for 2026-27 are 28 February 2027, 28 April 2027 and 28 July 2027. The GST turnover thresholds decide if a business registers. Mandatory registration applies at A$75,000, or A$150,000 for non-profit organisations.

## Who this applies to

- All Australian businesses registered for GST
- Employers with PAYG withholding obligations
- Companies with PAYG instalments
- Employers with FBT instalment obligation

## What to file

BAS form via ATO portal or accounting software with G1–G20 (GST), W1–W4 (PAYG W/H), 5A (PAYG instalment) and FBT fields completed.

## How to file

Online via ATO Online Services for Business, myGov (sole traders), or directly from software such as Xero or MYOB.

## Payment due

Same date as the BAS: pay via BPAY, direct debit, credit card or EFT.

## What happens if you miss it

Failure to Lodge (FTL) penalty: 1 penalty unit per 28 days late, up to 5 units. The penalty unit is A$364 for documents due on or after 1 July 2026, so the cap is A$1,820. The base penalty is multiplied by 2 for a medium withholder and by 5 for a large withholder. General Interest Charge on unpaid amounts is 11.43% a year for July to September 2026.

## Submission checklist

- Reconcile sales and GST collected (G1–G3)
- Reconcile purchases and GST credits (G10–G14)
- Calculate net GST (1A or 1B)
- Total wages and PAYG W/H (W1, W2)
- Apply PAYG instalment (5A) using ATO instalment notice
- Lodge and pay by 28 October

## Documents you need

- Sales invoices, purchase invoices and bank statements for the quarter
- Payroll summary showing wages and PAYG withheld
- PAYG instalment notice from the ATO
- Records of fuel tax credits or other claims if relevant

## Common mistakes to avoid

- Treating GST-free as input-taxed (different rules)
- Forgetting reverse charge for imported services
- Missing the deadline assuming tax agent extension (must lodge through agent to get it)
- Claiming GST on entertainment or private expenses
- Using a lodgment concession that does not apply: the Q2 BAS gets no extra extension because its date already includes one

Source: https://www.ato.gov.au/businesses-and-organisations/preparing-lodging-and-paying/business-activity-statements-bas/lodging-and-paying-your-bas/due-dates-for-lodging-and-paying-your-bas