Tom Talks Microsoft Teams and Microsoft 365 news and opinions

Using Microsoft Teams to join a Zoom or Webex meeting via Skype for Business SIP Address

Many popular meetings platforms like Zoom and Webex have an option to add a SIP Address for Skype for business users to dial directly into the meeting from the Skype for Business client.

It’s not the slickest user experience and not something I would necessarily recommend. Still, interestingly you can dial this SfB SIP URI from Microsoft Teams to join the Zoom or Webex or another platform meeting.

You are probably better joining with the native client for those platforms.

This works via federation, so you need to be in Teams Only mode (which allows federation) and have federation enabled. Unfortunately, most Teams users won’t know what “mode” they are in.

How do Zoom and Webex meetings get a Skype for Business Join SIP URI?

In Zoom, it is an option that the person inviting you to the meeting has to enable. e.g. in Zoom details are here


In Webex, there is a special format SIP URI you can dial,

More details here

Dialling the Skype for Business SIP address from Microsoft Teams to join a Zoom Meeting

In this example, I’ll use Zoom, but it will be much the same for any meeting platform that allows SfB SIP URI dial-in.

If the zoom user has the feature enabled, at the very bottom of the invite, there is a link to “Join by Skype for Business.”


That link takes you to a web page that is just a button to launch a link to a SIP URI. I’m not sure why they don’t put the SIP URI in the invite, maybe to allow click to launch SfB, possibly to avoid users confusing it with the standard non-SfB SIP URI in the invite.


If you have SIP: associated with Microsoft Teams, it will try to launch Teams


Otherwise, you may be given a selection of apps to choose from.


Or you might need to take this SIP URI and paste it into a new chat in Teams then “search externally.”


You can see in Teams it shows as a SfB federated contact, you can click the video call button, top right.


You will see audio and video working.


You can input the password to join the Zoom meeting with the keypad.




How does it work?

This works on the Teams desktop client (electron) and mobile app. I found it wasn’t working for me in the web app, though logically it should.

What is happening here is, even though the Teams desktop and mobile clients don’t have SIP in them, they can connect to an Office 365 gateway to allow SfB federation. This call is going via that SfB federation gateway.

The Teams user needs to be in Teams only; otherwise their federation is still via Skype for Business and must have federation enabled.

Microsoft Teams Rooms

Microsoft Teams Rooms can also do this, but they are actually dual-stack clients, they have an SfB client that makes the call directly without using the Office 365 gateway. They also have an upcoming feature to natively join WebEx and Zoom meetings which will be a superior user experience.

What about Cloud Video Interop (CVI)?

Cloud Video Interop (CVI) is about enabling standards-based rooms to dial into Microsoft Teams meetings, it doesn’t enable Teams to dial out to a standards-based room.

About the author

Tom Arbuthnot

A Microsoft MVP and Microsoft Certified Master, Tom Arbuthnot is Principal Solutions Architect at Microsoft Collaboration specialists Modality Systems.

Tom stays up to date with industry developments and shares news and his opinions on his blog, Microsoft Teams Podcast and email list. He is a regular speaker at events around the world.


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  • Seems that this no longer works
    Or is it just me?
    I remember doing this not even that long, like two weeks ago and it was still working. But not anymore, is that correct?

    • I’ve the same issue. i was able to dial WebEx but now i’m unable to dial Zoom or webex

        • seems to work sometimes…sometime I get the “We can’t set up the conversation because your organizations are not set up to talk to each other”
          Just a different Zoom meeting everything else the same. Doesn’t seem to be any reason why some work – some don’t

  • Any ideas on how to join a Zoom Personal Audio Conference from a Teams meeting? We can do this today from Teams by dialing into a PINless Zoom meeting, but Zoom is about to mandate PINs for all meetings and since you cannot send DTMF tones from Teams to Zoom, we are wondering how Zoom might be set up to accept a SIP call from Teams.

  • Does not seem to work any longer for Teams rooms. 1 have no way to enter anything other then numbers from Teams Room dialpad. 2. In my testing I get an error “Lync Connector is not enabled for this meeting.” (so might still work if the other party has above free zoom)

Tom Talks Microsoft Teams and Microsoft 365 news and opinions