What Is Microsoft Teams Calling? | Plain English Guide for UK Businesses
Microsoft Teams Calling is the ability to make and receive calls to and from standard phone numbers — mobiles, landlines, and international numbers — directly within the Microsoft Teams application. It requires a Teams Phone licence (£6–£12/month) and a Calling Plan or Direct Routing setup. This guide explains how it works, what it costs, and who it suits.
AMVIA Team
Editorial
Most UK businesses already run Microsoft Teams for chat and video. Teams Calling adds the missing piece: real phone calls to and from numbers outside your organisation. Below we explain how it works, what licences and connectivity you need, what it costs, and where it is the right call — and where a dedicated business VoIP platform serves you better.
How does Microsoft Teams Calling actually work?
Teams Calling uses Voice over Internet Protocol (VoIP) to carry calls as digital data over your internet connection. To reach the public phone network, Teams needs a PSTN gateway, supplied by Microsoft (Calling Plans), a certified carrier (Operator Connect), or a third-party session border controller (Direct Routing).
The important distinction is between two call types:
- Teams-to-Teams calls — audio and video between Teams users in your organisation. These work by default in any Microsoft 365 subscription, at no extra cost.
- External PSTN calls — calls to and from standard landlines and mobiles. These require an add-on licence plus a PSTN connection.
Once it is configured, the day-to-day experience is simple. A user opens Teams on any device, picks the Calls tab, and dials a number or contact. The business number assigned to that user rings across desktop, laptop, and mobile at the same time, so a call follows the person rather than a desk. Microsoft documents the underlying Teams Phone architecture in its Teams Phone technical guidance.
What do you need to enable Teams Calling?
You need three things stacked on top of each other: a Microsoft 365 subscription that includes Teams, a Teams Phone add-on licence for PBX features, and a PSTN connection that links Teams to the outside phone network. None of these replaces your existing Microsoft 365 plan — they extend it.
1. An existing Microsoft 365 subscription. Any Microsoft 365 Business or Enterprise plan already includes Teams. Microsoft lists current UK pricing — Business Basic £4.60, Business Standard £9.60, and Business Premium £16.90 per user per month (ex VAT, annual commitment) — on its Microsoft 365 plans page. Teams Calling builds on whichever plan you hold.
2. A Teams Phone licence. This add-on enables PBX functionality — auto-attendant, call queues, voicemail, and call transfer. It costs approximately £6–£12 per user per month and is not included in most standard plans, although it is bundled into Microsoft 365 E5.
3. PSTN connectivity. This is the link to the outside phone world, and you have three routes to choose from.
Which PSTN connection should you choose?
There are three ways to connect Teams to the public telephone network: Microsoft Calling Plans, Operator Connect, and Direct Routing. The right one depends on call volume, whether you want to keep an existing carrier, and how much control you need over routing and cost. The table below summarises the trade-offs.
| Connection method | How it works | Best for | Trade-off |
|---|---|---|---|
| Microsoft Calling Plans | Microsoft supplies numbers and minutes directly | Small teams wanting the simplest, fully Microsoft-managed setup | Approximately £5–£9/user/month; least flexible on carrier and tariff |
| Operator Connect | A certified carrier (e.g. BT, Gamma) provides PSTN through Microsoft's managed cloud | Businesses that want carrier choice without managing hardware | Limited to Microsoft-approved operators |
| Direct Routing | A third-party SBC connects Teams to a SIP carrier | Higher call volumes or keeping an existing carrier contract | More configuration; usually needs a partner to deploy |
For most UK SMEs we work with, Operator Connect or Microsoft Teams Direct Routing hits the sweet spot — competitive call rates and the freedom to keep a preferred carrier, without the management overhead of running your own SBC. Our managed Microsoft Teams calling service handles the procurement and configuration end to end.
What can Microsoft Teams Calling do once it is live?
Fully deployed, Teams Calling delivers the full feature set of a modern cloud phone system — external calling worldwide, UK numbers per user, automated call routing, and analytics — all inside one app. There is no separate phone system to learn or maintain alongside Teams.
A complete Teams Calling deployment provides:
- External calls to any phone number worldwide
- A UK phone number assigned to each user
- An auto-attendant to route inbound calls professionally
- Call queues for team-based inbound handling
- Voicemail with transcription
- Call forwarding, transfer, and park
- Call history and analytics in the Teams Admin Centre
- Support for Teams-certified IP desk phones
- Full operation across mobile, desktop, and web
Adoption tells the story. Microsoft Teams Phone has seen rapid, sustained growth in PSTN users worldwide, while the closest dedicated competitor, Zoom Phone, had reached 7 million paid seats as of Q3 2024 (Grand View Research). The direction of travel is clearly toward consolidating telephony into the collaboration app businesses already run.
Who is Teams Calling right for — and who should look elsewhere?
Teams Calling is the strongest choice for businesses already using Teams heavily for meetings and chat, and for organisations with significant remote or hybrid working. The payoff is one app for every kind of communication, with no context-switching between a separate phone system and Teams. It is not always the best fit for telephony-led or contact-centre-heavy operations.
It shines where:
- Teams is already the daily hub for meetings and messaging
- Staff work across multiple devices and locations
- You want a single, accountable provider for collaboration and voice — see how we combine VoIP with Microsoft 365
A dedicated hosted phone system may serve you better when telephony is the core of the business — for example, a busy sales floor or a contact centre with complex queueing, wallboards, and high call volumes. In those cases a specialist VoIP platform often offers deeper call-handling features and simpler administration at a comparable cost.
With the PSTN switch-off retiring traditional analogue and ISDN lines, every UK business needs an internet-based voice plan regardless. Teams Calling is one of the cleanest ways to land in that future-proof position, particularly when paired with sensible VoIP security controls.
Add External Calling to Microsoft Teams
AMVIA handles the complete Teams Calling setup for UK businesses — licence assessment, Calling Plan or Direct Routing, number porting, and user rollout.
Frequently Asked Questions
Teams-to-Teams audio and video calls between users in your organisation are included in every Microsoft 365 plan. External calling — to mobiles, landlines, and international numbers — is not. That requires a Teams Phone add-on licence plus either a Microsoft Calling Plan, Operator Connect, or Direct Routing connection to the public phone network.
Yes. Existing UK numbers can be ported into Teams Calling via Microsoft Calling Plans or a Direct Routing carrier. Porting typically takes around 10–15 working days. You can also request brand-new UK geographic numbers from Microsoft in the area code you need, so you are never forced to change your published number.
Yes. The Teams app for iOS and Android fully supports external calling on your business number, with answer, hold, transfer, and voicemail. Push notifications make calls ring on the handset even when the app is closed, so staff stay reachable on their work number without sharing personal mobiles.
Budget for two add-ons on top of your existing Microsoft 365 subscription: a Teams Phone licence (roughly £6–£12/user/month) and, if you use Microsoft for connectivity, a Calling Plan (roughly £5–£9/user/month). Microsoft 365 E5 already includes Teams Phone, so E5 customers pay only for the calling connection.
Teams uses HD audio and adaptive codecs that adjust to available bandwidth, so on business-grade broadband or fibre call quality is consistently high. Quality depends on a stable, low-latency connection. The Teams Admin Centre includes call-quality analytics so your IT team or provider can monitor and troubleshoot any issues.
For most UK SMEs, yes. Teams Calling covers the core of a business phone system — auto-attendant, call queues, voicemail, transfer, recording (with Teams Premium), and analytics. Businesses with complex contact-centre needs or very high call volumes may need additional certified solutions layered on top of Teams Phone.
Related Reading
Microsoft Teams Phone System | Included with 365?
What Teams Phone System includes, what it costs, and how to add it to your Microsoft 365.
Microsoft Teams Calling Features | What's Possible
A full breakdown of Teams Phone features — what is included and what requires add-ons.
Microsoft Teams Calling Plans | What Are They?
How Microsoft Calling Plans provide phone numbers and call minutes for Teams Phone users.