Highlights

  • Registered tax agents need to lodge overdue prior-year returns and add relevant new clients to their client list by 31 October 2026.
  • Missing the deadline can mean affected clients do not receive the concessional due dates available under the tax agent lodgment program.
  • The ATO has warned that the 31 October deadline still applies even though the date falls on a weekend.
  • Client-to-agent linking and system update times mean agents should act well before the end of October.

Registered tax agents have a key deadline of 31 October 2026 to clear certain overdue prior-year returns and add new clients to their client list.

The Australian Taxation Office has warned that failing to complete these steps in time can affect whether clients receive the extended lodgment due dates available through the tax agent lodgment program.

For agents carrying overdue work or onboarding new clients, the practical message is to act early rather than leave the process until the final days of October.

What has to happen by 31 October

By 31 October 2026, tax agents need to ensure that relevant overdue prior-year returns have been lodged and that new clients are properly added to their client list.

Where these requirements are not met, affected clients may not receive the lodgment-program due date for their 2026 return.

Instead, they may remain subject to an earlier general lodgment date.

That makes prior-year compliance important not only for historical obligations but also for preserving access to later due dates for the current return.

The date does not move to the next Business day

One important timing issue is that 31 October 2026 falls on a weekend.

Because 31 October 2026 falls on a Saturday, the ATO's standard administrative rules mean that obligations can technically be met on the next business day, Monday, 2 November 2026.

However, relying strictly on that final weekend rollover can be risky for clients whose eligibility for the agent lodgment program depends on clearing prior obligations or linking profiles on time. Agents should therefore aim to complete the necessary work well before the weekend wherever possible to account for processing and system updates.

Allow time for due dates to update

Another practical issue is the time it can take for client due dates to update after an overdue prior-year return is lodged.

The ATO advises that system updates can take up to three weeks.

During that period, the client's current-year due date may not immediately reflect the later lodgment-program date.

Agents should therefore avoid assuming that an unchanged due date means the client is ineligible.

The ATO's guidance also suggests avoiding unnecessary deferral requests while the system is still processing the prior-year lodgment.

Client-to-agent linking

Some new clients need to complete client-to-agent linking before a registered tax agent can add them to the client list.

That process requires action by the client, which means the agent cannot always complete onboarding unilaterally.

Clients may need to nominate the tax agent before the agent can finalise the relationship in ATO systems.

For that reason, new-client onboarding should begin well ahead of 31 October.

Leaving the linking process until the last week can create avoidable timing risk if the client does not complete their part promptly.

Who may be affected and what to do

Registered tax agents and their clients are directly affected, particularly where:

  • prior-year tax returns remain overdue;
  • a new client has recently engaged the agent;
  • client-to-agent linking is required; or
  • the client's current due date has not yet updated in ATO systems.

Agents should review their client lists now and identify any clients whose access to the lodgment program may depend on action before 31 October.

Overdue prior-year returns should be prioritised, while new clients should be guided through any required linking steps early.

What is at stake for clients

One of the practical benefits of using a registered tax agent is access to the ATO's lodgment program, which can provide later due dates than those applying to taxpayers who lodge independently.

But those later dates are subject to eligibility conditions.

If a client's prior-year obligations remain outstanding or the client is not properly linked to the agent by the relevant cut-off, the later due date may not apply.

That can leave the client facing an earlier lodgment deadline and potentially increase the risk of late-lodgment penalties if the return is not filed in time.

The deadline therefore matters to both the agent and the client.

Practical timing traps

There are three main timing issues to manage.

The first is the weekend deadline. Agents should not assume 31 October automatically shifts to the next working day.

The second is system processing. A prior-year return may be lodged correctly, yet the updated current-year due date may not appear for up to three weeks.

The third is client-to-agent linking. Where required, the process depends on the client completing their nomination before the agent can finalise the relationship.

Taken together, these timing issues make early action important.

What tax agents should prioritise now

Agents should focus on four practical steps:

  1. identify clients with overdue prior-year returns;
  2. lodge those returns well before 31 October;
  3. review new clients who still need to be added to the agent list; and
  4. start client-to-agent linking early where it applies.

It is also useful to monitor ATO systems after lodgment rather than immediately assuming a due-date problem if the change is not visible.

The key message is straightforward: 31 October is not just an administrative cut-off. It can determine whether a client retains access to the concessional due dates available under the tax agent lodgment program.