Telstra VoIP Shutdown: What Australian Businesses Need to Do Before September 2026

If your business phone system runs through Telstra's SIP, VoIP, or inbound number services, you are on a platform that is being permanently switched off. Some services already stopped accepting new customers in 2024. Others are shutting down completely through to September 2026. This guide covers the exact timeline, who is affected, what happens to your phone numbers, and the steps to migrate without losing service. Prices are in AUD including GST.

What Is Actually Happening (In Plain Language)

Telstra built its business phone infrastructure on older technology -- SIP trunking and VoIP platforms that require significant ongoing investment to maintain. Rather than upgrade them, Telstra has decided to exit these products and push business customers toward its cloud-based services or leave customers to find alternatives.

This is not unusual in the Australian telco market. The broader PSTN copper network was switched off in 2025, and carriers have been accelerating the retirement of legacy voice products ever since. Telstra's shutdown affects specific product lines, not everything they sell. The key is knowing exactly which products are going away.

The Shutdown Timeline: What Has Already Gone and What Is Next

The shutdown is happening in stages. Here is the timeline as it stands:

November 2024 -- already done: Telstra stopped accepting new connections for 1300 and 1800 inbound number services. If you already had one, it kept working. But no new numbers could be added to the platform after this date.

November 2025 -- already done: All remaining 1300 and 1800 inbound services hosted on Telstra's legacy platform are being ended. Customers on these services should have received migration notices. If you have not acted, your inbound numbers may already be at risk.

September 2025 -- already done: Telstra stopped accepting new connections for its Call Termination Services (CTS). Existing CTS customers could keep using the service, but no new setups were possible after this date.

September 2026 -- the final deadline: Telstra's Call Termination Services shut down completely. All remaining CTS customers lose service. This is the hard deadline for anyone still on these products.

Who Is Affected

You are affected if your business uses any of these Telstra products:

• Telstra Business SIP -- SIP trunking service that connects your existing phone system to the Telstra network
• Telstra Digital Office Technology (DOT) -- a hosted business phone system product aimed at small and medium businesses
• Telstra Call Termination Services (CTS) -- used by businesses and carriers to route calls across the Telstra network
• Telstra-hosted 13, 1300, and 1800 inbound numbers -- if Telstra manages the routing for your 1300 or 1800 number, not just the line

If you are unsure which product you have, check your Telstra bill. The product name should be listed under your business phone services. You can also call Telstra Business Support on 13 2000 and ask specifically whether your services are affected by the SIP and CTS shutdown.

Who Is NOT Affected

A lot of businesses are understandably confused about what Telstra is switching off. To be clear, the following are separate products and are not affected by this shutdown:

• Telstra mobile services -- your mobile phone plans, SIM cards, and mobile fleet are completely separate from the VoIP/SIP shutdown
• Telstra NBN broadband -- your internet connection is not affected. The shutdown is about voice products, not data
• Telstra Adaptive Collaboration -- this is Telstra's newer cloud communications platform (based on Microsoft Teams voice and other cloud services). This is not being shut down -- it is the direction Telstra is pushing customers toward
• Telstra phone plans on NBN -- if you have a basic home-style line bundled with NBN, check whether this is an ATA-based service (see below) rather than the SIP products listed above

What Happens to Your Phone Numbers

This is the question most businesses worry about most. The good news: you own your phone numbers, not Telstra. Under the Australian Communications and Media Authority (ACMA) framework, phone numbers -- including geographic numbers, 1300 numbers, and 1800 numbers -- can be ported to a new provider.

Number porting is the process of transferring your existing phone number from one carrier to another. Your new provider initiates the port on your behalf. For most standard business numbers, the process takes 5 to 10 business days. For 1300 and 1800 numbers, the process is similar but may involve ACMA's inbound number registry, which can add a few extra days.

The critical rule: do not cancel your Telstra service before the port completes. If you cancel first, you may lose the number entirely. Your new provider should manage this sequence for you -- but confirm it with them explicitly before signing anything.

For a detailed walkthrough of the porting process, see Number Porting in Australia: How It Works for Business.

Your Options: What Can Replace Telstra's Services

The replacement category is broadly called hosted VoIP or cloud PBX. These are phone systems that run over the internet rather than traditional phone lines. Here is what that means in practice:

• Your calls travel over your internet connection instead of a dedicated phone line
• The phone system itself lives on a server somewhere else (not in your office), managed by your provider
• You get features you probably do not have now -- hold music, auto-attendant (the "press 1 for sales" menu), ring groups, voicemail to email, call recording, softphone apps for mobiles and laptops
• You keep your phone numbers via the porting process described above
• Cost is typically per seat per month, usually in the range of $25 to $60 per user per month including GST depending on the plan

"Cloud PBX" and "hosted VoIP" are often used interchangeably. PBX stands for Private Branch Exchange -- it is the system that manages calls within your business (extensions, transfers, hold, etc.). A cloud PBX does this from a server your provider manages, rather than a box in your server room.

For an introduction to how these systems work and what to look for, see What Is VoIP? A Plain-Language Guide for Australian Businesses.

How to Migrate Before the Deadline: Step by Step

Here is the practical sequence most businesses should follow:

Step 1 -- Confirm which Telstra products you have. Call Telstra Business on 13 2000 or log into your Telstra Business account and look at your phone services. Write down the product names and the phone numbers on each service.

Step 2 -- Audit your current call flows. How do calls come in to your business right now? Do you have a receptionist? An auto-attendant? A 1300 number? Multiple lines? Ring groups? Write down what you have and what you need. This tells you what features your new system must support.

Step 3 -- Check your internet connection. Hosted VoIP runs over your NBN or business internet. The quality of your calls depends on your upload speed and how much traffic is on your connection. As a rule of thumb, each simultaneous call needs about 100 Kbps of reliable upload bandwidth. A business with 5 staff taking calls at the same time needs at least 500 Kbps of dedicated upload capacity. Use the VoIP Bandwidth Calculator to check whether your current connection can handle your call volume.

Step 4 -- Get a cost estimate. The costs vary significantly depending on your team size, the features you need, and whether you need new handsets. Use the VoIP Cost Calculator to get a ballpark figure for your situation before approaching providers.

Step 5 -- Choose a provider and sign up. Look for Australian-based providers with local support, a clear SLA, and experience with number porting. Your new provider will manage the migration process, including the port of your existing numbers from Telstra.

Step 6 -- Plan your cutover date. A cutover is when you switch from your old system to the new one. Plan this for a low-traffic period (early morning, late Friday, public holiday eve). Your provider should give you a cutover checklist. See VoIP Cutover Checklist for Australian Businesses for what to prepare.

Step 7 -- Do not cancel Telstra until the port is confirmed complete. This is the most common mistake. Wait for written confirmation from your new provider that all numbers have ported successfully before cancelling your Telstra account.

For a full migration walkthrough, see How to Migrate Your Business Landline to VoIP in Australia.

How Much Will It Cost

Costs vary by team size and features, but here are realistic ballpark figures including GST:

• 1 to 5 users: $30 to $50 per user per month for a basic plan. Total: $150 to $250/month.
• 6 to 20 users: $25 to $45 per user per month. Total: $150 to $900/month depending on features.
• 20 to 50 users: Pricing typically scales down per seat. Expect $20 to $40 per user per month at this volume.
• Handsets (if needed): Basic SIP desk phones from $90 to $200 each. Mid-range models $200 to $350 each.
• Number porting fees: Usually $0 to $30 per number depending on the provider.
• Setup / installation: Many providers offer self-setup. Managed installation for larger offices typically $500 to $2,000 depending on complexity.

For a personalised cost estimate, use the VoIP Cost Calculator. For a deeper breakdown of what drives costs, see VoIP Costs in Australia: What to Actually Expect.

What Most Businesses Get Wrong

Mistake 1: Waiting until the last minute. The September 2026 deadline sounds distant, but number porting takes 5 to 10 business days and providers have intake queues. If every affected Telstra business tries to migrate in the three months before September 2026, wait times will blow out. Start now -- the process is not complicated, and migrating six months early costs you nothing while waiting until the last month could cost you your phone service.

Mistake 2: Cancelling Telstra before the port is done. If you cancel your Telstra service before your phone numbers have successfully ported to your new provider, you can lose those numbers permanently. The porting process only works when the number is still active with the losing carrier (Telstra). Always get written confirmation that the port is complete before cancelling anything.

Mistake 3: Not checking the internet connection first. Many businesses assume their existing NBN service is fine and discover during setup that their upload speed is not enough for reliable calls, or that the connection drops during peak hours. Run the bandwidth check before you sign a contract, not after. Your provider should also do this, but do not rely on them being thorough -- check it yourself with the Bandwidth Calculator.

Mistake 4: Assuming Telstra will handle the migration for you. Telstra will notify you that your service is ending. They will not automatically migrate your numbers or set up your new system. You need to choose a new provider and initiate the process. Telstra's communications will often suggest their own products (like Adaptive Collaboration), but you are free to go to any provider -- and you should compare before deciding.

Your Next Steps

• Confirm with Telstra which specific products your business uses (call 13 2000 or check your bill)
• Write down all your business phone numbers and the services they run on
• Audit your call flows -- what features do you use, what features do you need?
• Run the Bandwidth Calculator to confirm your internet can handle your call volume
• Use the Cost Calculator to get a ballpark cost for your migration
• Get a provider recommendation matched to your setup
• Book your cutover date with your new provider well before September 2026
• Wait for porting confirmation before cancelling Telstra

Will Telstra automatically move my numbers to a new service?

No. Telstra will notify you that your service is ending, but they will not automatically port your numbers to a new provider. You need to choose a replacement service, sign up, and instruct your new provider to port your numbers from Telstra. The porting process takes 5 to 10 business days for most business numbers.

I have a 1300 number. What happens to it?

If your 1300 number is hosted on Telstra's legacy inbound number platform, it was affected from November 2025. You can port a 1300 number to a new provider, and your customers will never know anything changed. The process goes through ACMA's inbound number registry and typically takes a few days longer than a standard geographic number port. Do not cancel your Telstra service before the port is confirmed complete.

Does this affect my Telstra mobile phones?

No. The shutdown affects Telstra's SIP, VoIP, and inbound number products only. Your Telstra mobile plans, SIM cards, and mobile data services are completely separate products and are not being discontinued.

Does this affect my Telstra NBN internet?

No. The shutdown affects Telstra's voice products only. Your Telstra NBN broadband service is not affected. However, if you currently have a Telstra-provided phone service bundled with your NBN -- such as a voice line through an ATA adapter connected to your modem -- check whether that voice service is part of the shutdown. If it is, your internet will keep working but the phone line will stop.

How long does migration take?

From the day you sign up with a new provider to the day your numbers have ported and your new system is live, most small business migrations take 2 to 4 weeks. This includes signing up, provisioning your new phone system, testing, and completing the number port. Larger or more complex setups may take longer. Plan for at least 4 weeks to be safe, and more if you need new hardware delivered and installed.

What is the difference between SIP trunking and hosted VoIP?

SIP trunking connects your existing on-premise phone system (the box in your office) to the internet for calls. Hosted VoIP (or cloud PBX) replaces the on-premise system entirely -- the phone system itself lives in the cloud. For most small businesses migrating off Telstra SIP, moving to hosted VoIP is simpler and cheaper than maintaining an on-premise system with a different SIP trunk provider.

Will my calls sound worse on VoIP?

With a properly configured system on a reliable NBN connection, call quality on hosted VoIP is equal to or better than the old copper PSTN network. The risk factors are an underpowered internet connection, a router that does not prioritise voice traffic (QoS settings), and a provider with poor peering. Use the Bandwidth Calculator to check your connection, and ask any provider you are considering about their call quality SLA before signing up.

For more on the PSTN shutdown and what it means for Australian businesses more broadly, see PSTN Shutdown Australia: What Businesses Need to Know.