Highlights

  • The ATO has outlined five common income tax return due dates that frequently prompt questions from clients.
  • Due dates can depend on entity type, prior-year tax outcomes, registration status and when a client was added to an agent’s list.
  • Large and medium entities can fall into different January or February dates depending on whether they were taxable or non-taxable.
  • Agents should confirm each client’s actual ATO due date rather than relying only on broad categories.

Few things confuse clients more than why their tax return is due on a particular date, and the Australian Taxation Office has published a quick guide to five common income tax return due dates and the circumstances in which they apply.

In guidance for tax professionals released in August 2026, the ATO explained that a client’s due date can depend on factors including entity type, prior-year outcomes, registration status and when the client was added to an agent’s client list.

31 October

The 31 October due date can apply to clients with overdue prior-year returns, clients added to an agent’s client list after the relevant cut-off, and taxpayers the ATO has specifically advised are required to lodge by that date.

This can include taxpayers with a history of serious non-lodgment issues.

For tax agents, 31 October is therefore an important date to watch for clients who may not qualify for later dates under the lodgment program.

31 January

The 31 January due date generally applies to taxable large and medium entities, other than individuals, based on their most recently lodged income year.

It can also apply to taxable head companies of consolidated groups that include a medium or large member.

The classification of the entity and its prior-year taxable status are therefore important in determining whether this date applies.

28 February

The 28 February due date covers a different group of entities, including certain non-taxable large and medium entities.

It can also apply to:

  • new registrant large and medium entities;
  • non-taxable head companies of consolidated groups;
  • certain entities that have exited a consolidated group; and
  • new registrant self-managed super funds.

This is a good example of why apparently similar entities can receive different due dates depending on their registration and prior-year circumstances.

31 March and 15 May

The 31 March due date, excluding relevant large and medium entities, applies to several categories of taxpayers with higher prior-year liabilities or income.

This can include individuals and trusts with a prior-year tax Liability of $20,000 or more, as well as certain companies and super funds with income above $2 million.

It can also apply to consolidated group heads where relevant income thresholds are met.

The 15 May date is the general lodgment-program due date for many remaining entities that are not required to lodge earlier and do not fall within another concession or exception.

Who may be affected and what to do

Every tax agent and client can potentially be affected because lodgment dates are determined by individual circumstances rather than by a single universal rule.

When a client questions their due date, agents should look at factors such as:

  • entity type;
  • taxable or non-taxable status;
  • prior-year tax liability;
  • income level;
  • registration status;
  • consolidated-group status; and
  • when the client joined the agent’s client list.

The most reliable approach is to confirm the due date shown through the ATO’s systems for that particular client.

Why due dates differ so much

The lodgment program spreads tax-return work across the year and applies different dates according to taxpayer circumstances.

That means two clients who appear similar at first glance can legitimately have different deadlines.

For example, one company may fall into a January date because it was taxable in the latest lodged year, while another similar-sized entity may fall into February because it was non-taxable or newly registered.

Likewise, an individual with a larger prior-year tax liability may receive an earlier date than another individual using the same tax agent.

Understanding those drivers helps agents explain due dates clearly and set expectations early.

Using the dates to manage workflow

For tax practices, the five dates are also useful workflow markers.

Large and medium entities can cluster around January and February, while higher-liability individuals and trusts, along with certain companies and super funds, can fall into the March cycle.

Many other clients sit within the May lodgment program.

The 31 October date deserves particular attention for clients with overdue prior-year obligations or those added to an agent’s list after the relevant cut-off, because these clients may not qualify for later lodgment-program dates.

Confirming each client’s due date early allows practices to prioritise work and identify clients who risk losing access to a concessional date.

Do not assume every client in a category has the same date

One point worth emphasising is that these dates are broad lodgment-program categories rather than a substitute for checking an individual client’s actual ATO record.

Deferrals, prior compliance history, substituted accounting periods and other circumstances can affect the date that ultimately applies.

Agents should therefore use the ATO’s guidance as an explanation tool while relying on the client’s recorded due date for practical lodgment planning.