Whether you lodge a Business Activity Statement (BAS) or an annual income tax return — or both — depends on your business structure, GST registration status, and the types of taxes you are obliged to report. Most registered businesses will encounter both obligations at different points, and understanding which applies when can save you from late-lodgement penalties and unnecessary stress.
What is a BAS and who needs to lodge one?
A Business Activity Statement, commonly called a BAS, is a form you submit to the Australian Taxation Office (ATO) to report and pay several tax obligations in one place. The most common taxes reported on a BAS include Goods and Services Tax (GST), Pay As You Go (PAYG) withholding for employees, PAYG instalments, Fringe Benefits Tax (FBT) instalments, and the Luxury Car Tax or Wine Equalisation Tax where applicable.
You are generally required to lodge a BAS once you register for GST. According to the (ATO), you must register for GST if your business turnover meets the relevant registration threshold. Even if you are not registered for GST, you may still receive a BAS-style instalment notice if you are required to pay PAYG instalments on your business or investment income.
Sole traders, partnerships, companies, trusts, and not-for-profit organisations can all have BAS obligations. The key trigger is activity: if you are collecting GST from customers, withholding tax from staff wages, or paying PAYG instalments, the ATO will expect a BAS lodgement.
What is an annual tax return and who must lodge one?
An annual income tax return is a separate obligation lodged once per financial year. It reports your total assessable income, allowable deductions, and calculates your overall tax liability for that year. Individuals, companies, trusts, partnerships, and self-managed superannuation funds (SMSFs) each have their own version of this return.
For individuals, including sole traders, the return covers the full income year from 1 July to 30 June. For companies and other entities, different lodgement deadlines and forms apply. The ATO publishes lodgement due dates on its website; if you use a registered tax agent, you may be eligible for extended deadlines under the Tax Agent Lodgment Program. You can find a registered tax or BAS agent through the (Tax Practitioners Board public register).
Unlike the BAS, which is an ongoing periodic obligation tied to your trading activity, the annual return is a comprehensive summary of your financial year. Missing this lodgement can attract general interest charges and failure-to-lodge penalties from the ATO.
Key differences between the two obligations
The simplest way to distinguish the two is by timing and scope. A BAS is lodged monthly, quarterly, or annually depending on your reporting cycle and covers activity-based taxes as you go. An annual income tax return is lodged once per year and captures the full picture of your income and deductions.
Another important difference is that a BAS primarily deals with amounts you have collected or withheld on behalf of the government, such as GST from customers and PAYG withholding from employees. Your annual return, by contrast, determines how much tax you personally or your entity owes on net taxable income after deductions.
It is also worth noting that not everyone who lodges an annual return will need a BAS. An employee with no business activities, for example, lodges an annual individual tax return but has no BAS obligation. Conversely, a small business owner registered for GST will almost certainly need to lodge both.
BAS lodgement frequency: monthly, quarterly, or annually?
The ATO assigns your BAS reporting cycle based on your business size and circumstances, though you can apply to change it. Most small businesses are placed on a quarterly cycle. Larger businesses with higher withholding or GST obligations may be required to report monthly. Very small businesses meeting certain criteria may be eligible for an annual GST reporting option.
Quarterly BAS lodgements are generally due around the 28th of the month following the end of each quarter, though dates shift around public holidays. The ATO provides a full lodgement and payment calendar on its website at (ATO lodgement dates). If you lodge through a registered BAS or tax agent, different due dates may apply.
Choosing the right frequency matters: lodging monthly gives you more regular reconciliation points and may help cash flow management, while quarterly lodgement reduces administrative burden. Discuss your situation with a registered agent to determine what suits your business best.
When you need both at the same time
Most operating businesses in Australia will face both obligations simultaneously. Each quarter, you lodge your BAS to account for GST collected, PAYG withholding, and any instalments owing. Then, once the financial year closes on 30 June, you or your accountant will prepare an annual income tax return reconciling the year's income against deductions and any PAYG instalments already paid.
The PAYG instalment system is specifically designed to link the two. When you pay PAYG instalments through your BAS throughout the year, those payments are credited against your annual income tax liability when you lodge your return. This prevents a large tax bill arriving all at once after the financial year ends.
If you operate a company, trust, or SMSF, you will also face entity-specific return obligations. SMSF trustees, for instance, must lodge an annual SMSF annual return, which combines income tax, regulatory, and member information reporting. More information is available from (ASIC) for company obligations and the ATO for SMSF requirements.
Common mistakes Australians make with BAS and returns
One frequent error is confusing GST collected with income. The GST component of your invoices belongs to the ATO, not to you, and treating it as revenue creates distorted records that flow through to your annual return. Keeping GST funds in a separate account throughout the quarter is a practical habit many accountants recommend.
Another common issue is missing lodgement deadlines. Both BAS and annual returns have firm due dates, and the ATO actively follows up outstanding lodgements. Penalties can accumulate quickly for businesses that fall behind, so setting calendar reminders or working with a registered agent is worthwhile.
Claiming incorrect deductions on an annual return is also a persistent issue. The ATO provides detailed guidance on deductible expenses at (ATO deductions), but the rules vary by entity type and industry. If you are uncertain about a claim, consult a registered tax agent rather than guessing.
For more detailed cost expectations when engaging a professional, see our cost guide, and if you are looking for qualified help in your city, browse our listings of best accountants in Sydney or review our methodology to understand how we evaluate practitioners.
Comparison: BAS versus annual return at a glance
| Feature | BAS | Annual Income Tax Return | |---|---|---| | Frequency | Monthly, quarterly, or annual | Once per year | | Main purpose | Report GST, PAYG withholding, instalments | Report total income, deductions, final tax liability | | Who lodges | Businesses registered for GST or PAYG | Individuals, companies, trusts, partnerships, SMSFs | | Key authority | ATO | ATO | | Agent assistance available | Yes, via registered BAS or tax agent | Yes, via registered tax agent |*Note: No fees or rates are included in this table as those are subject to change; refer to the ATO directly for current figures.*
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FAQ
Q: Do I need to lodge a BAS if I am not registered for GST? A: You may still receive an instalment activity statement (IAS) from the ATO if you have PAYG withholding or instalment obligations, even without GST registration. Check your obligations via the (ATO). Q: Can I lodge my BAS and annual return myself, or do I need an agent? A: You can lodge both yourself through the ATO's online services. However, a registered tax or BAS agent can assist with accuracy, extended deadlines, and strategic advice. Verify an agent's registration at the (Tax Practitioners Board). Q: What happens if I lodge my BAS late? A: The ATO may impose failure-to-lodge penalties and general interest charges on any tax owing. The longer the delay, the greater the potential penalties. Contact the ATO promptly if you have fallen behind, as they do have processes for working with businesses in genuine difficulty. Q: If my business is new, when does my BAS obligation start? A: Your BAS obligation generally begins as soon as you register for GST or have PAYG withholding obligations. The ATO will notify you of your lodgement cycle after registration. More detail is available at (ATO — new to business essentials).---
Sources
- Australian Taxation Office -- BAS information: https://www.ato.gov.au/businesses-and-organisations/preparing-lodging-and-paying/business-activity-statements-bas - Australian Taxation Office -- main site: https://www.ato.gov.au/ - Tax Practitioners Board public register: https://www.tpb.gov.au/public-register - Treasury -- tax policy: https://treasury.gov.au/ - ASIC -- company and SMSF obligations: https://asic.gov.au/ - Income Tax Assessment Act 1997 (AustLII): https://www.austlii.edu.au/cgi-bin/viewdb/au/legis/cth/consol_act/itaa1997240/
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Information in this article is general only and not tax or financial advice. Verify the details with the linked sources or an appropriately qualified Australian professional before relying on them.
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