Moving Business Numbers to Microsoft Teams: A Practical Migration Guide
A practical migration plan for moving UK business numbers and call flows to Microsoft Teams without unnecessary disruption.
Moving business numbers to Microsoft Teams combines a number port with a voice-platform migration. The Teams tenant, PSTN connectivity, users, policies and call flows should be ready before customer numbers are transferred.
Choose the Teams PSTN model
Confirm whether numbers will use Calling Plans, Operator Connect, Teams Phone Mobile or Microsoft Teams Direct Routing. The selected model determines the provider, number process and technical responsibilities.
Inventory numbers and dependencies
List main numbers, DDIs, ranges, fax, alarms and services linked to the current account. Record the losing provider, account, installation address and purpose of each number. Identify broadband or bundle dependencies.
Rebuild call flows in Teams
Document reception, auto attendants, queues, schedules, voicemail, overflow and out-of-hours behaviour. Recreate only what is still useful; migration is an opportunity to remove obsolete routes without changing the core customer journey unexpectedly.
Prepare users and policies
Assign validated licences, number policies, dial plans and routing policies. Create resource accounts for queues and auto attendants where required. Use approved domains and role-based administration.
Test with temporary numbers
Before the port, test inbound and outbound calls, presentation, transfer, hold, voicemail, DTMF and failure routing. Include different networks and representative users. Confirm that support teams can access useful Teams and provider diagnostics.
Submit a validated port order
Use the exact losing-provider records and complete range. A managed business number port should identify rejection risks before a live date is agreed.
Plan cutover and coexistence
Large organisations may migrate in phases. Define temporary routing between the old system and Teams, avoid overlapping extension plans and make ownership clear. Do not leave an undocumented hybrid route in place indefinitely.
Test at the live event
Call every important number from external fixed and mobile services. Verify outbound identity, queues, schedules and voicemail. Keep old services available until the provider confirms port completion and the agreed acceptance tests pass.
Support users after migration
Provide short guidance for dialling, transferring, audio selection, voicemail and queue status. Monitor call quality and failed calls. Capture timestamps and call examples for diagnosis.
Migration checklist
- Select and design the PSTN connectivity model.
- Audit numbers, ranges and associated services.
- Configure tenant, users, policies and call flows.
- Test with temporary numbers.
- Validate and schedule the port.
- Run acceptance tests and monitor live use.
The port should be the final controlled step, not the start of configuration. Ask I.T Communications to plan your Teams number migration.
