Porting in ~30 phone numbers - should we request placeholders?

Question

We are going to be porting in roughly 30 DIDs soon, but in preparation, should we go ahead and acquire new "temp" numbers for these so that we can build out our processes and test everything? My concern is that there could be limits on number of active DIDs and would rather get those kinks worked out now as opposed to during the porting process. Any guidance is appreciated (We have an MS support agreement but for some reason the portal will not allow creating support requests).

Answer 1

Hi @mark baker
Yes, it is a good practice to acquire a few temporary or test phone numbers before initiating a bulk port of around 30 DIDs. This allows you to configure and validate your call flows, voice routing policies, auto attendants, call queues, emergency location settings, and user assignments in advance without the time pressure of an active porting window. In Microsoft Teams Phone environments, there is generally no strict tenant-level limit that would prevent you from temporarily holding additional service numbers, but it is still important to confirm licensing availability and number capacity for your specific region and calling setup. Testing with placeholder numbers helps identify configuration issues early and reduces the risk of service disruption during the actual porting cutover.
https://learn.microsoft.com/en-us/microsoftteams/phone-number-calling-plans/transfer-phone-numbers-to-teams?tabs=new-porting-wizard

Answer 2

Hi @mark baker

Yes—using temporary (placeholder) phone numbers is a supported and recommended approach when preparing to port a larger batch of numbers (such as ~30 DIDs) into Azure Communication Services (ACS). You can acquire a small number of ACS phone numbers upfront and use them to build and test call and SMS flows, routing, event handling, and integrations before the port completes, which helps avoid issues during the cutover window. Once the ported numbers appear in your ACS resource, they can simply replace the temporary numbers in your configuration, and the placeholders can be released if no longer needed. Microsoft does not document a hard limit on the total number of active phone numbers per ACS resource; published limits mainly apply to phone number search and purchase operations, and Azure Support can assist with bulk or quota‑related scenarios if required. This approach aligns with Microsoft guidance and effectively addresses concerns around scale and porting readiness.

References:

• Port a phone number into ACS: https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/telephony/port-phone-number
• Service limits for ACS: https://learn.microsoft.com/en-us/azure/communication-services/concepts/service-limits
• Phone number types & subscription eligibility: https://learn.microsoft.com/en-us/azure/communication-services/concepts/telephony/plan-solution

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