Microsoft Teams Calling: A Comprehensive Guide for UK Businesses

Most UK businesses are already leveraging Microsoft Teams for internal communication and meetings. Microsoft Teams Calling extends the platform’s capabilities to handle traditional telephone calls – both outbound to mobile and landline numbers and inbound from external parties. When fully implemented, Teams can function as a business’s sole communication application.

A crucial distinction exists between Teams-to-Teams calls, which are included in any Microsoft 365 subscription, and external PSTN calls, which necessitate additional licenses and configuration. This guide focuses on external calling functionality within Microsoft Teams.

How Microsoft Teams Calling Works

Microsoft Teams Calling utilizes Voice over Internet Protocol (VoIP) to transmit calls as digital data over the internet. To connect to the public telephone network (standard phone numbers), Teams requires a PSTN gateway. This gateway can be provided through three primary methods: Microsoft Calling Plans, Operator Connect (via a certified carrier), or Direct Routing (using a third-party Session Border Controller or SBC).

From the user’s perspective, the process is straightforward:

• Open Microsoft Teams on any device.
• Select the ‘Calls’ tab.
• Dial the desired phone number or select a contact.
• Make and receive calls as you would with a traditional desk phone.

A business number assigned to the user rings simultaneously on all their Teams-enabled devices – desktop, laptop, and mobile.

What You Need for Microsoft Teams Calling

• Existing Microsoft 365 Subscription: Any Microsoft 365 Business or Enterprise plan includes Microsoft Teams. Teams Calling is an extension of this existing subscription, not a replacement.
• Teams Phone Licence: An add-on license, typically costing between £6 and £12 per user per month, enables PBX functionality such as auto-attendant, call queues, voicemail, and call transfer. This license is not included in most standard Microsoft 365 plans (with the exception of E5).
• PSTN Connectivity: The connection to the external telephone network. Options include:
  • Microsoft Calling Plans: Microsoft provides phone numbers and call minutes, generally priced between £5 and £9 per user per month. This is a simple, fully managed solution.
  • Operator Connect: A certified carrier (such as BT or Gamma) provides PSTN connectivity through Microsoft’s managed cloud. This offers carrier choice without the complexity of managing an SBC.
  • Direct Routing: A third-party SBC connects Teams to a SIP carrier. This is the most flexible option, particularly suitable for high call volumes or businesses with existing carrier relationships.

Key Features of Microsoft Teams Calling

• External calls to any phone number globally.
• Dedicated UK phone number(s) assigned to each user.
• Professional inbound call routing via auto-attendant.
• Team-based inbound call handling with call queues.
• Voicemail with transcription services.
• Call forwarding, transfer, and park functionalities.
• Comprehensive call history and analytics.
• Support for Teams-certified IP phones.
• Seamless operation across mobile, desktop, and web devices.

Who is Microsoft Teams Calling Right For?

Microsoft Teams Calling is particularly well-suited for businesses that already heavily utilize Microsoft Teams for meetings and internal communication. The primary benefit is a unified communication experience – eliminating the need to switch between separate phone systems and Teams.

It’s also a strong choice for organizations with significant remote or hybrid workforces, where the mobile app experience and cross-device availability of Teams Calling offer practical advantages over traditional desk-phone-centric VoIP systems.

For businesses with limited reliance on Microsoft 365, a dedicated hosted VoIP platform from a specialist provider may offer more telephony-specific features and simpler call management at a comparable cost.

Companies like IQTeams offer simplified Microsoft Teams Phone systems specifically designed for UK small businesses, with transparent pricing and UK-based support.

The Looming PSTN Switch-Off

UK businesses should be aware of the impending 2027 PSTN (Public Switched Telephone Network) switch-off, which will require all organizations still relying on legacy copper lines or ISDN to modernize their telecommunications infrastructure.