How to Port Your Business Number from Telstra to VOIP (Step-by-Step)

This guide covers the exact steps to port a Telstra business phone number to a VOIP provider in Australia, based on how the Australian number portability system actually works. You will know the correct order of operations, what Telstra-specific complications to watch for, how long the process takes, and the single mistake that can leave your business without a phone number. The process is more straightforward than most people expect, but the failure modes are specific and avoidable.

What Number Porting Actually Means

Number porting is the legal right, under ACMA regulations, to transfer your phone number from one carrier to another while keeping the number itself. When you port from Telstra to a VOIP provider, your number moves across the Australian telecommunications numbering system without changing. Customers calling your old Telstra number will reach you on your new VOIP system the moment the port completes. Nothing changes for callers.The process is initiated by your new provider, not by you or by Telstra. This is an important distinction. You do not contact Telstra to start the port. You contact your new VOIP provider, give them the details of your Telstra service, and they submit the porting request to the industry portability system on your behalf. Telstra is then notified and has a set processing window. Your role is to keep your Telstra service active and provide accurate account details. See our full guide to number porting in Australia for an overview of how the system works across all carriers.

Step 1: Choose Your VOIP Provider Before You Do Anything Else

The single most important rule of leaving Telstra is to choose and sign up with your new VOIP provider before doing anything else. Do not call Telstra to give notice, do not downgrade your Telstra plan, and do not let your Telstra service lapse. Your Telstra service must remain active and in good standing for the port to succeed. If the service is cancelled or disconnected before the port completes, the number may be returned to the numbering pool and lost permanently.When evaluating VOIP providers, confirm porting capability explicitly before signing up. Most reputable Australian hosted VOIP providers support standard geographic number porting, but timelines and documentation requirements vary. Ask each provider: do you support porting from Telstra? What is your typical porting timeline for a standard service? Do you charge a one-off porting fee? What documentation do you need? Our guide to the best VOIP phone systems for Australian small businesses covers providers with proven AU porting capability.

Step 2: Understand Your Telstra Service Type

The type of Telstra service you are porting determines how complex and how long the process will be. Geographic numbers with a local area code (02, 03, 07, 08) on a standard Telstra line are almost always Category A ports: the simplest type, with standard timelines and minimal documentation. Most small business phone numbers on Telstra's standard products fall into this category.Category C ports apply to more complex services: numbers on ISDN, multiline bundles, hosted IP products, or some NBN voice configurations. These require Telstra's active cooperation, take longer, and carry a higher rejection risk. If your Telstra service has more than two or three lines, or if it was delivered over an ISDN connection, treat it as a potential Category C port until your new provider confirms otherwise. Our detailed explanation of Cat A vs Cat C porting in Australia covers what each category means in practice.

Step 3: Gather Your Telstra Account Details

Your new provider will need specific details from your Telstra account to submit the porting request. Gather these before you contact your new provider: the phone number or numbers to be ported, your Telstra account number (printed on your Telstra bill), the authorised contact name listed on the account, and your Telstra service address. Some providers also require a copy of a recent Telstra bill as supporting documentation.Accuracy matters here. Discrepancies between the details on the porting authority form and Telstra's account records are the most common cause of port rejections. Pull your account number, name, and address directly from a current Telstra bill rather than from memory. Small differences in address formatting or business name spelling are enough to trigger a rejection. Getting this right on the first submission avoids a resubmission delay of several business days.

Step 4: Complete the Porting Authority Form

Your new provider will give you a porting authority form (sometimes called a letter of authorisation). This is a legal document that authorises your new provider to initiate the transfer on your behalf. Every field on this form must match your Telstra account records exactly. Common errors include variations in business name spelling, abbreviation of street address types (St vs Street), and using an address that differs from the Telstra-registered service address.Once completed, your new provider submits the form to the industry portability system. Telstra is notified and has a defined window to process the request. You will receive a porting date from your new provider once the submission is accepted. For what happens when a submission is rejected, see our guide to number porting rejection reasons and how to fix them.

Porting Timelines: What to Expect

Category A ports from Telstra typically complete in 5 to 10 business days from submission, assuming accurate documentation and no complications. Most standard small business geographic number ports fall into this range. Plan for 10 business days as your working estimate so you have buffer if any clarification is needed. Category C ports take considerably longer. Allow 20 to 30 business days as a working estimate and confirm the expected timeline with your new provider before planning your cutover. For ISDN services, the timeline depends on Telstra's workload and your specific configuration. Do not commit to a cutover date with staff or clients until your new provider has confirmed the porting date. Our guide to number porting timelines in Australia explains the staging in detail.

The Golden Rule: Never Cancel Telstra Before the Port Completes

This is the single most important rule in the entire migration process. Do not cancel, downgrade, or give notice on your Telstra service until you have received written confirmation from your new provider that your number has successfully transferred. Cancelling Telstra early is the most common cause of number loss during a migration. Telstra's billing team and Telstra's porting team operate independently. If you call Telstra about your account for any reason during the porting window, avoid mentioning cancellation. A well-meaning operator who processes an early cancellation can disrupt a port in progress even if the request is already in the system.

How to Stay Reachable During the Transition

Most hosted VOIP providers provision your account with a temporary number immediately on signup. This lets you configure call routing, test your phones and headsets, and train staff on the new system before your main number moves across. During the porting window, share the temporary number with key contacts as a backup.On the porting date, the cutover is near-instantaneous. There is typically no window where calls to your number simply fail. The number stops routing through Telstra and begins routing through your VOIP system within minutes. Many providers schedule the cutover overnight to minimise business disruption. Your new provider will advise the expected cutover time when they confirm your porting date.If you also have a 1300 number on your Telstra account, note that 1300 porting is handled separately from geographic line porting and follows a different process. Read our guide to porting a 1300 number to VOIP before initiating that part of the transfer.

Australian Businesses: Telstra's Network Changes and What They Mean

Telstra's copper telephone network has been progressively decommissioned as the NBN rolled out across Australia. The PSTN (Public Switched Telephone Network) was shut down nationally in 2025. If you are still on a Telstra business phone service today, you are on a digital service: either NBN voice delivered through an NBN connection, or Telstra's IP platform, or in some areas a transitional service.This matters for porting because the underlying service type affects your port category. A Telstra number now delivered over the NBN is typically a simpler port than one previously on a legacy ISDN circuit. Confirm with your new provider what type of Telstra service your number is currently on before submitting. The practical implication of the PSTN shutdown: Telstra's business phone product is now just another VOIP service, typically bundled with NBN broadband at a higher price than a standalone specialist VOIP provider. For more context on what this shift means, see our guide to migrating from a landline to VOIP in Australia.

What Most Businesses Get Wrong When Leaving Telstra

Mistake 1: Cancelling the Telstra account before the port completes. Already covered above, but it bears repeating: this is the most dangerous error in the entire process. Keep the account active and paid until your new provider confirms the transfer is done.Mistake 2: Not checking what type of Telstra service you have. Assuming a simple Cat A port when the service is actually Cat C means underestimating the timeline. A business that plans a cutover two weeks out on a Cat C service will likely miss that date. Confirm the service type with your new provider as the very first step.Mistake 3: Not setting up the new VOIP system before the porting date. Businesses that wait until the port completes before touching the new system often discover configuration problems on cutover day. Set up call routing, test handsets, configure voicemail, and confirm ring groups are working at least a week before your number is due to move.Mistake 4: Committing to a cutover date before it is confirmed. Do not inform staff or clients of a cutover date until your new provider has given you a confirmed porting date from the portability system. Estimating a date based on the submission date alone leads to rushed communication if there is a delay.Mistake 5: Ignoring early termination clauses in the Telstra contract. Number porting does not cancel your Telstra contract. After the port completes, you need to separately cancel your Telstra service. Check your contract for early termination fees before you start the process so there are no surprises when you cancel after the port.

Your Next Steps

1. Choose your VOIP provider and sign up for an account. Confirm they support porting from Telstra and ask for their typical timeline for your service type.
2. Retrieve your Telstra account details from a current bill: account number, authorised contact name, service address, and the numbers to be ported.
3. Set up and test your new VOIP system using the temporary number your provider gives you. Configure call routing, voicemail, and ring groups. Confirm all handsets are working before the port date.
4. Complete the porting authority form from your new provider. Check every field against your Telstra bill for exact match.
5. Keep your Telstra service active and paid throughout the porting window. Do not contact Telstra about cancellation until after the port is confirmed complete.
6. On the porting date, test incoming calls from a mobile to confirm the number is routing to your new VOIP system.
7. After confirmed completion, contact Telstra to cancel or downgrade remaining services. Get written confirmation of the cancellation date and any final bill amount.

Can I port my Telstra number while still under contract?

Yes. You have the legal right to port your number at any time regardless of your contract status. However, porting the number does not cancel your Telstra contract. You will still be liable for any early termination fees when you cancel the service after the port. Check your Telstra contract for early exit terms before initiating the process.

Does Telstra charge a fee to release my number?

Telstra does not charge a porting-out fee for most standard geographic numbers. The fee risk is in your contract: if your Telstra service is on a fixed term, early termination charges apply when you cancel the service after the port completes. The port itself is separate from the cancellation.

Will there be any downtime when my number moves?

For a standard port, the cutover is near-instantaneous. There is typically no window where calls to your number fail. Many providers schedule the cutover overnight or early morning to minimise any potential disruption. Your provider will advise the expected cutover time when they confirm your porting date.

Can I port multiple Telstra numbers at once?

Yes. Multiple geographic numbers on a Telstra account can be included in a single porting request. For complex services such as ISDN with multiple lines, all lines typically need to be ported together or sequenced carefully. Discuss multi-number porting with your new provider before submitting to agree on the approach.

How do I confirm the port is complete?

Your new VOIP provider will notify you when the port is confirmed complete. Verify by calling your number from a mobile phone. If the call rings on your new VOIP system rather than the old Telstra service, the port is done. Do not cancel your Telstra account until you have verified this directly.

What if my porting request is rejected?

Port rejections are usually caused by a mismatch between the porting form and Telstra's account records. Your new provider will explain the rejection reason. In most cases the fix is correcting the specific field that mismatched and resubmitting. The timeline resets from resubmission but you do not lose your number. See our guide to number porting rejection reasons for a full list of causes and resolutions.