It’s common for an organization to want to restrict where a user or phone can call outside an organization, especially long distance tolled calls. There are a number of different ways to do this, with a variety of different administrative impacts.
If a user has calling plans, the first way would be to only license the account for domestic calling, versus domestic and international. If you do this, note that adding a Communications Credit license to the user will allow them to make international calls on a pay-as-you-go basis. You might want communications credits assigned to a Calling Plan user to allow them to continue to make outgoing calls once the “per user per month” pooled minutes expire. If that’s the case, you’ll need to implement an additional method discussed below.
Regardless of whether a user’s PSTN service is via Calling Plans, Operator Connect, or Direct Routing, you can restrict where they can call in Teams Admin Center:
Here, I can block outbound calling entirely with “Don’t allow”, permit international calling with “Any destination” or only to Karl’s own country/region with the middle option “In the same country or region as the organizer”.
The text here – specifically the word “organizer” – would lead you to believe that this is for dialout from meetings. However, it does also apply to PSTN calls Get-CsOnlineDialOutPolicy (SkypeForBusiness) | Microsoft Learn
Note that this restriction will apply regarding of Operator Connect, Direct Routing, or Calling Plans being the PSTN connectivity option for the user.
This isn’t a terribly granular capability. If you’re on Operator Connect, your operator may be able to do some extra screening for you. There are some other solutions that may work well, or at least well enough, for your scenario, in my next post.