What Is Microsoft Teams Calling? | Plain English Guide for UK Businesses

Microsoft Teams Calling: The Plain English Explanation

Most UK businesses are already using Microsoft Teams for meetings and internal messaging. Microsoft Teams Calling extends that same application to handle real telephone calls — outbound calls to mobile numbers and landlines, and inbound calls from outside the organisation. When fully set up, Teams becomes the only phone application a business needs.

The key distinction is between Teams-to-Teams calls — which work by default in any Microsoft 365 subscription — and external PSTN calls, which require additional licences and configuration. This guide focuses on external calling: calling and receiving calls from standard UK phone numbers.

How Teams Calling Works

Microsoft Teams Calling uses 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 needs a PSTN gateway — provided either by Microsoft (Calling Plans), a certified carrier (Operator Connect), or a third-party SBC (Direct Routing).

Once configured, the process from a user's perspective is straightforward:

1. Open Microsoft Teams on any device
2. Select the Calls tab
3. Dial any phone number or select a contact
4. Make and receive calls exactly as you would with a traditional desk phone

The business number assigned to the user rings in Teams on all their devices — desktop, laptop, and mobile — simultaneously.

What You Need for Teams Calling

Existing Microsoft 365 Subscription

Any Microsoft 365 Business or Enterprise plan includes Teams. Teams Calling builds on this — you are not replacing your Microsoft 365 subscription, you are extending it.

Teams Phone Licence

An add-on licence, approximately £6–£12/user/month, that enables PBX functionality: auto-attendant, call queues, voicemail, call transfer. Not included in most standard Microsoft 365 plans (except E5).

PSTN Connectivity

The connection to the outside telephone world. Three options:

• Microsoft Calling Plans: Microsoft provides numbers and minutes — £5–£9/user/month. Simple, fully managed by Microsoft.
• Operator Connect: A certified carrier (BT, Gamma) provides PSTN via Microsoft's managed cloud. Carrier choice without SBC complexity.
• Direct Routing: A third-party SBC connects Teams to a SIP carrier. Most flexible; best for higher call volumes or existing carrier relationships.

What Teams Calling Can Do

When fully deployed, Microsoft Teams Calling provides:

• External calls to any phone number in the world
• UK phone number(s) assigned to each user
• Auto-attendant to route inbound calls professionally
• Call queues for team-based inbound call handling
• Voicemail with transcription
• Call forwarding, transfer, and park
• Call history and analytics
• Teams-certified IP phone support
• Working on mobile, desktop, and web across all devices

Who Teams Calling Is Right For

Teams Calling is the strongest choice for businesses that already use Microsoft Teams heavily for meetings and internal communication. The benefit is a single application for all communication — there is no context switching between a separate phone system and Teams.

It is also a strong choice for businesses with significant remote or hybrid working, where the mobile app experience and cross-device availability of Teams Calling provides practical advantages over a traditional desk-phone-centric VoIP system.

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

AMVIA assesses Teams Calling requirements for UK businesses and provides fully managed deployment — from licence procurement through to number porting, auto-attendant configuration, and user training.