You update your ABN details through ABR online services at abr.gov.au, logging in with your myID. It is free, changes take effect immediately, and you are required to make them within 28 days of becoming aware of the change. That covers your address, contact details, authorised contacts and business activities. It does not cover your name or your business name, which are changed elsewhere.
What the 28-day rule actually requires
Keeping your ABN details current is an obligation, not a courtesy. The clock runs from when you become aware of the change, not from when you get around to it, and it applies to every detail held against the ABN.
Your ABN record is public through ABN Lookup, and other people rely on it. A client checking whether you are registered for GST before paying your invoice is reading this record. So is a government agency trying to reach businesses in a particular postcode after a flood or a fire, which is the reason the register asks for a physical street address rather than a postal one.
How to update your ABN details online
- Go to abr.gov.au and open ABR online services.
- Log in with your myID. You will need a Relationship Authorisation Manager link to the business, which you will already have if you have lodged online before.
- Select Update ABN record.
- Choose the section you need: business address, postal address, contact details, authorised contacts, or ANZSIC and business details.
- Make the change, then select Declaration and Submit.
Changes made online take effect immediately. If you cannot get in, you can contact the ABR and do it by phone, complete and mail the paper form, or ask your registered tax agent to make the change for you. All three are free.
How to change the address on an ABN
There are two addresses on the record and they do different jobs. Getting them the wrong way round is the most common mistake on this form.
- Main business address: the physical street address where the business operates. It cannot be a post office box, and it cannot be your accountant's or BAS agent's address. If you work from home, it is your home address.
- Postal address: where you want government mail sent. This one can be a PO box, and it can be your tax or BAS agent's address. Use it if you do not want correspondence going to the street address.
- Additional locations: if you operate from more than one place, each is listed separately, and each must also be a street address.
This is the section worth checking even if nothing has changed. Plenty of sole traders registered years ago and have moved house since without thinking of the ABN as something that moves with them.
Adding or changing your business activity
Your ABN carries a main business activity, recorded as an ANZSIC industry code, and you can register up to four additional activities alongside it. It is used for statistics and for matching you to government programs, not to limit what you are allowed to do, so an out-of-date code does not make your invoices invalid. It does make you invisible to anything targeted at the work you actually do now.
Worth updating when the business has genuinely shifted. A designer who now does most of their work as a photographer, or a tradesperson who has added a maintenance contract line, has a main activity that no longer describes them. Add the second activity rather than replacing the first if you still do both.
What you cannot change through ABR online services
Five things are not editable in the portal, and each has a different route. This is where most of the wasted time on this task goes, because the form does not explain where to go instead.
| You cannot change | Where it is changed instead |
|---|---|
| Your legal name, as a sole trader | Change it with the ATO directly. The ABN record updates automatically once the ATO holds the new name. |
| A company name | Change it with ASIC. It flows through to the ABN record without you doing anything at the ABR. |
| A registered business name | ASIC Connect. A business name is a separate registration that sits against your ABN rather than inside it. |
| Entity type | Not a change at all. A different structure is a different legal entity, so it needs a new ABN and the old one is cancelled. |
| Trading names | Trading names are historical. They stopped being maintained on the register, so the replacement is a registered business name with ASIC. |
The pattern is that the ABR does not own these fields. Your legal name is the ATO's, your company name is ASIC's, and your business name is ASIC's too. Change them at the source and the ABN record updates itself, which is why trying to do it from the ABN side never works.
Changing your legal name as a sole trader
A sole trader's ABN is held in their own legal name, so marrying, divorcing or otherwise changing your name means changing it with the ATO, not with the ABR. Once the ATO has it, the ABN record follows automatically. Do not cancel and re-apply for this, which is a surprisingly common piece of bad advice: it is the same entity with a different name.
Changing entity type is not an update at all
Moving from sole trader to company, or to a partnership or trust, is not a change of details. It is a different legal entity, so it needs its own ABN, and the old one gets cancelled once the changeover is done. If that is what you are doing, start with the structure decision, then cancel the old ABN in the right order.
What to check while you are in there
This is a fifteen-minute job you will do roughly once a year, so it is worth a short list rather than a single edit:
- Is the business address still where you work? A street address, not a PO box.
- Does the email address still reach you? This is where the register and the ATO write, and an old work address on a domain you no longer own means you never see it.
- Are the authorised contacts right? Remove anyone who no longer acts for the business, including a former accountant.
- Does the main business activity still describe the work?
- Is your GST registration status what you expect? It shows on ABN Lookup, and clients check it. If you crossed the threshold and never registered, that is a different and more urgent job.
That last one is worth acting on rather than noting, because the GST threshold is a rolling test rather than an end-of-year one, and the obligation starts the month you cross it.
Related reading
- How to get an ABN: entitlement, and what the application asks for
- How to cancel an ABN: when the change is that you have stopped
- How to reactivate a cancelled ABN: getting the number working again
- How to register a business name: the ASIC registration, not the ABN one
- ABN vs ACN: which number a company changes where
- Do I need to register for GST?: the status clients read off your record
Frequently asked questions
Twenty-eight days from becoming aware of the change. It applies to your address, contact details, authorised contacts and business activities, and the clock starts when you know about the change rather than when you get around to it.
No. Updating through ABR online services at abr.gov.au is free, and so is doing it by phone or by posting the paper form. A registered tax agent can also make the change for you as part of what they already do.
Not as the main business address, which has to be the physical street address where the business operates and cannot be your accountant or your BAS agent’s address either. You can use a PO box for the postal address, which is where government mail is sent.
Through the ATO, not the ABR. A sole trader ABN is held in your legal name, so once the ATO has the new name the ABN record updates itself. Do not cancel the ABN and apply again, because it is the same entity under a different name.
Changes made through ABR online services take effect immediately. Updates made by phone or by posting the paper form take longer, so use the online route if you need the change reflected on ABN Lookup quickly.
You are in breach of an obligation, and more practically you stop receiving things. Government correspondence goes to the old address, clients checking ABN Lookup see stale information, and an ABN showing no signs of current activity is a candidate for cancellation by the register.
Sources
The 28-day requirement, the address rules, the limit on additional business activities and the list of details that cannot be changed in ABR online services come from the Australian Business Register. Procedures change, so confirm the current position at abr.gov.au or ato.gov.au, or with a registered tax agent. Balaana is bookkeeping software, not a tax agent. This article is general information, not personal tax advice.