Telstra Calling for Office 365 is being withdrawn on 30 November 2026. If your business makes external phone calls through Microsoft Teams with this service, those calls stop working on that date.

The service, usually called TCO365, is the connection between Microsoft Teams and the Australian phone network. Microsoft has not announced anything here. Telstra has. Teams itself stays exactly where it is.

Here are the key dates, what actually stops working, and how to move without losing your numbers.

What Telstra Calling for Office 365 does

Teams on its own cannot dial the public phone network. Chat, meetings and files run inside Microsoft’s cloud. To reach a landline or mobile, Teams needs a carrier connection behind it.

TCO365 was Telstra’s version of that connection. It bundled a phone number and Telstra carriage underneath your Microsoft 365 licences. One product, one bill.

The withdrawal dates are published in Telstra’s critical information summary and its customer terms for the service.

Three dates you cannot ignore

The Telstra Calling for Office 365 retirement runs on three milestones. Two of them have already passed.

The August date matters more than it looks. Even if your service runs fine today, you cannot add a new user, move a number or adjust a plan. The planning window closed while most people were still reading the announcement.

TCO365 is one of several Telstra SMB products being wound down. Our sunset guide covers the rest.

What this means for your business

Separate what is going away from what is not.

• Microsoft Teams stays active. Chat, meetings, channels and collaboration carry on.
• External calls stop through Telstra. After 30 November 2026, calls made or received through this Telstra integration will stop working.
• Your numbers need a new home. Numbers port cleanly only while the service is still active.
• Your Microsoft licensing is unaffected. You are replacing carriage, not Microsoft.

Expect a migration conversation from Telstra too. Their in-house alternative is Operator Connect with Telstra. It is a legitimate option. See how the pricing stacks up in our SIPcity vs Telstra comparison before anyone signs.

Your three replacement paths

Microsoft supports three ways to connect Teams to the phone network. Every TCO365 customer ends up on one of them.

1. Microsoft Operator Connect. Microsoft-certified partners provide calling you provision directly inside the Teams admin centre. Simple, limited to the partner’s plan.
2. Microsoft Teams Direct Routing. You connect Teams to a compatible carrier yourself. Maximum control, and the widest choice of carriers and call flows.
3. Teams Phone Mobile. Calling rides on a mobile number and carrier plan instead of a fixed line. Fits mobile-first staff, availability depends on participating carriers.

For most TCO365 businesses, Operator Connect and Direct Routing are the realistic answers. If you are comparing carriers more broadly, our guide to Telstra business voice alternatives covers the rest of the field.

SIPcity Teams Connect: Direct Routing built for Australian Teams

SIPcity Teams Connect is our answer to exactly this situation: Teams Direct Routing at $24.99 per user per month, with unlimited local and Australian mobile calls included. Your people keep the native Teams dialer, desktop and mobile.

Teams Connect runs on the same platform as the SIPcity cloud phone system. Teams users and colleagues on desk phones share the same numbers, call queues and voicemail.

Carriage runs over SIPcity’s Australia-based network, so your calls stop taking trips overseas. Full plan details are on the Teams Connect plan page.

Direct Routing also gives you something the other paths do not: mixing. Teams Phone users, desk phones and legacy analogue systems sit on the same service, so nobody has to convert on the same day. Microsoft 365 Enterprise and Teams Phone licences are required per user, and you keep whatever licensing you already have.

Your IT team manages numbers through SIPcity Cloud PBX and assigns Teams numbers through the Teams admin centre.

A migration checklist that beats a November panic

A considered TCO365 exit is five steps. Start now and it lands comfortably before the cutoff.

1. Inventory everything. List your users, numbers and call flows. Auto attendant menus, call queues, ring groups, voicemail and recording settings all get rebuilt on the new service.
2. Choose your path. Compare Operator Connect and Direct Routing on price, number flexibility and support. Ask any provider what your call flows look like after the move.
3. Start your number ports early. Port while TCO365 is still active. Our number porting team coordinates directly with Telstra for you.
4. Rebuild and test. Recreate the call flows and place real test calls, inbound and outbound.
5. Keep both running briefly, then cut over. Overlap is cheap. A dead phone line on 1 December is not.

Number ports take weeks, not days. Five weeks left on the clock is workable, but only if you start this week.

The short version

Telstra Calling for Office 365 closes on 30 November 2026. Microsoft Teams is not going anywhere, but your external calling through Telstra is. The freeze started on 30 August, so the only decision left is which replacement, and how fast.

If you would like a second opinion on the options, talk to our team. We will map your numbers and call flows, quote Teams Connect against your current bill, and put a migration date on the calendar before the window closes.