When you install Microsoft Teams and start to use it for as your default calling app you want Teams to open when you click on TEL: URLs on homepages. A TEL: URL is in the format tel:<phonenumber> ex. tel:+46890510 and when you click on that Teams should open and you will be able to call that number without copy the number or type it manual in your Teams dialpad. In this article I will show how to configure Teams to be your default calling application for TEL: URLs.

When you create a homepage it’s important that you write the phone number in the correct format and that is the E164 format. Make the phone number clickable by making it to a link with the a href tag, this will make it easy for your customers to click on the phone number to call you. You can also use this format in your email signature or other HTML pages where you want people to be able to easily contact you.

<a href=”TEL:+46890510″>+46890510</a>

There is also the SIP: prefix that can be used for SIP addresses. The SIP address is the same format as an emailadress and the link should be SIP:firstname.lastname@lync.se. If you publish your SIP address in this format make sure that you have enabled external access in Teams and Skype Admin interface (Org-wide settings > External access) so that others can federate with you. Note that not all scenarios that worked in Skype for Business does not work in Microsoft Teams yet.

In the examples I will show how you can register TEL: and SIP: URLs to Microsoft Teams from a Windows 10 installation. Microsoft Teams can also open CALLTO:, IM: MSTEAMS: and SIPS: URLs.

Register URL association for Teams

  1. In your Edgebrowser write tel:<phonenumber> and press Enter ex. tel:+46890510
  2. This should ask you “How do you want to open this?”
    – Select Microsoft Teams.
    – Make sure “Always use this app” is selected
    – Press OK
  3. Microsoft Teams should now ask you “Would you like to call this number“?
  4. Do the same thing with an SIP: URL

URL is already registered with another APP

When you use the TEL: or SIP: url from Edge you might get this question “Microsoft Edge is trying to open Skype”, then there is already another application registered and you have to change to registration to Teams instead.


  1. Search for and open the Default app settings in Windows 10
  2. Scroll down and select Set defaults per app. Scroll down to Teams and click on Manage button.
  3.  You now see a list of all URLS that can be associated to Teams. If there is any application (Skype for Business in this examle) that you want to change, click on that application and change to Teams instead. Change for all protocols (CALLTO, IM, MSTEAMS, SIP, SIPS and TEL).

Use Group policy

You can also use a Group policy to change the URL association on multiple computers that are joined to you Active Directory.

  1. First do all associations that you would like to change from the default, include other applications too not just Teams.
  2. Open a cmd promts as administrator and run the following, this will export your DefaultAppAssociations to an XML file
    Dism /Online /Export-DefaultAppAssociations:c:\temp\AppAssoc.xml
  3. In the XML file you should see your associations

  4. https://docs.microsoft.com/en-us/internet-explorer/ie11-deploy-guide/set-the-default-browser-using-group-policy

  5. Open your Group Policy editor and go to the Computer Configuration\Administrative Templates\Windows Components\File Explorer\Set a default associations configuration file setting.

  6. Click Enabled, and then in the Options area, type the location to your default associations configuration file

More info about GPO here