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 business phone company 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 business phone company, 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 business phone company, 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 business phone company Before You Do Anything Else

The single most important rule of leaving Telstra is to choose and sign up with your new business phone company 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 number must remain active until the port completes. Telstra cannot refuse or delay the port merely because money is owing, although you remain liable for bills and contractual charges. If the number is disconnected before the port, it cannot be ported and you lose your current rights to use it. Disconnected numbers are generally quarantined for 6 to 12 months; if a telco disconnected the number in error, it must reissue it within one business day when asked.When evaluating business phone companies, confirm porting capability explicitly before signing up. Most reputable Australian cloud phone system companies 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. Category A is the default process for a simple service with a one-to-one relationship between the telephone number and the relevant carriage service. The gaining provider should confirm the category for the particular Telstra service.Category C is the default where the number is associated with a complex service requiring manual processing coordination, this can include numbers on ISDN, multi-number product groups, hosted IP products, or some NBN voice configurations. Neither the number of lines nor the underlying access technology alone determines the category, confirm with your new provider which category applies to your specific service. These generally take longer and carry a higher rejection risk than a standard Category A port. 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. Complete the authorisation accurately and use the service account number shown on the bill. Cat A rejections may also result from disconnected or pending-disconnection status, pending orders, an existing port request, a non-simple service or a non-portable access service. 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

For Category A ports from Telstra, 80% complete within 8 business days, 90% within 10, and 98% within 15 after confirmation, where infrastructure exists. Many standard small-business geographic-number ports use this process, although the service arrangement can require Category C handling. Plan for up to 15 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 can result in number loss because disconnected numbers cannot be ported. If you call Telstra about your account for any reason during the porting window, avoid mentioning cancellation. An early cancellation processed while a port is in progress can disrupt it, even if the porting request is already in the system.If a port request fails or is delayed, your VOIP provider will notify you with an error code and a reason. An incorrect service account number can cause a port request to fail. Other rejection grounds include service status, pending orders, an existing port request and an incorrect port category. Do not assume close enough will pass. The fix is usually to obtain a Telstra account summary from MyAccount or by calling 13 2200, then re-submit the porting form with the exact name and account number format shown on the Telstra document. Even minor differences like "Pty Ltd" versus "Pty. Ltd." can cause rejections. If a port is delayed without an error code, contact your VOIP provider directly -- they can query the port status through the inter-carrier LNP system. Your new provider coordinates the port and should be your first contact for port-status questions. Telstra still performs required losing-carrier validation, cutover and completion tasks, and remains the contact for faults affecting the existing service until transfer completes.

How to Stay Reachable During the Transition

If your provider offers a temporary number, it may be available during 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.Cutover is subject to activation targets rather than a no-downtime guarantee. For Cat A, at least 90% of valid cutover requests must be activated within 30 minutes and 99% within two hours. Ask the gaining provider about expected interruption and timing; after-hours cutovers require inter-carrier arrangements. 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. Telstra has migrated many fixed-phone services to NBN and IP platforms, but the PSTN was not shut down nationally in 2025. Telstra currently says it is not exiting copper PSTN voice services and still offers standalone Home or Business Phone service on copper where applicable.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. Telstra currently offers multiple business voice products, including PSTN, NBN/IP and cloud-based services. Whether a Telstra service is bundled with broadband and how its price compares with a specialist provider depends on the specific plans and inclusions. For more context on what this shift means, see our guide to migrating from a landline to VOIP in Australia.Fixed-line numbers (02, 03, 07, 08 area codes) and mobile numbers (04xx) port through different systems with different timelines. Fixed local numbers are ported under the Local Number Portability Code C540:2023. ACMA says individual local-number ports are generally completed within 8 to 15 business days, while more complex ports can take up to 30 business days, subject to limited exceptions. Mobile number porting is handled through the MNP (Mobile Number Portability) system and typically completes within 4 hours on a business day. If your business currently uses a Telstra mobile as its primary number and you want it to ring through your VOIP system, the porting process is different: you port the mobile number either to a virtual carrier SIM or directly to a VOIP provider that supports mobile number acceptance. Not all VOIP providers support mobile number porting -- confirm this explicitly before choosing a provider if a mobile number is involved.

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, check which Telstra services were deactivated and which associated services remain. The port deactivates voice service on the ported local number, but associated broadband, equipment or other services may require separate cancellation. 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 business phone company 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.

What Does Number Porting Cost?

Port-in fees vary by provider and port category. Some providers include simple Cat A ports, while others currently advertise about $20-$44 for a simple port; complex Cat C ports can cost substantially more. Telstra may charge an early termination fee if you are mid-contract, so check your agreement before initiating the port. The ongoing cost after porting is the cloud phone plan: $20-35 per user per month (inc. GST, for a standard plan with Australian calls included, as at August 2026). Whether a business pays less per month after moving to a cloud plan depends on the plans’ call inclusions, bundling, licences, support, hardware and contract terms.

If you are still working out whether a cloud phone system is the right long-term choice for your business beyond the number port, our guide to cloud phone systems vs traditional phones for Australian businesses covers the full comparison, including ongoing cost differences, reliability on NBN, and the scenarios where sticking with a traditional service still makes sense.

If you are new to VoIP or want a broader overview of how number portability works when switching providers -- including which number types are portable, what account details to gather, and what happens on porting day -- see our guide: Can I Keep My Phone Number When Switching to VoIP in Australia?

Not sure what actually happens once you decide to switch? Read our plain-English guide to what happens when you change business phone provider, you don’t need to be technical to follow it.

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 port-out charges depend on the service and contract. Some products may have no charge, while current Telstra IP and collaboration products can impose administrative port-out fees; check the terms for the exact service. 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 business phone company 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.