Teams Calling Plan vs Operator Connect vs Direct Routing

Last checked: 26 October 2026

To make and receive outside calls in Microsoft Teams, each user needs a Teams Phone licence plus one of four ways to reach the phone network: a Microsoft Calling Plan, Operator Connect, Direct Routing or Teams Phone Mobile. A Calling Plan makes Microsoft your phone provider. Operator Connect lets a Microsoft-certified operator supply the numbers and calls with no equipment on your side. Direct Routing connects any carrier through a Session Border Controller (SBC) that you or a partner manage.

This guide compares the options for a UK business. If you are still deciding whether Teams should be your phone system at all, read our Microsoft Teams calling alternatives guide first.

What does Teams need before it can make outside calls?

Microsoft separates the phone system licence from the phone line. Its licensing guidance says: "Teams Phone requires a separate add-on license. For Teams Phone only, buy a Teams Phone Standard license. For users to make and receive external calls using the PSTN, you'll need to choose a PSTN connectivity option as well."

PSTN means the public switched telephone network: ordinary UK landline and mobile numbers. Microsoft's Teams Phone overview puts it this way: "A PSTN solution is separate from a Teams Phone license."

Is Teams Phone included in Microsoft 365 Business Premium?

No. According to Microsoft's Teams Phone licensing page, Microsoft 365 Business Basic, Business Standard and Business Premium are prerequisites for the Teams Phone Standard add-on, not plans that include it. The same page says a Microsoft 365 E5 licence includes the Phone System application, so E5 users do not need the separate Teams Phone Standard licence. They still need a way to connect to the phone network.

The four options at a glance

Microsoft's PSTN connectivity page describes four models and says they can be combined in the same tenant.

Question	Calling Plan	Operator Connect	Direct Routing	Teams Phone Mobile
Who supplies numbers and calls?	Microsoft	A Microsoft-certified operator	Any carrier you choose	A certified mobile operator
Who manages it?	"Microsoft-managed"	"Shared between your participating telecommunications provider and Microsoft Teams"	"Customer-managed Session Border Controller (SBC)"	"Participating mobile operator"
Equipment you need	None beyond Teams devices	None beyond Teams devices	A Microsoft-certified SBC (yours or hosted)	A business mobile on that operator
Extra contract	Microsoft Calling Plan licence	Contract with the operator	Contract with a carrier plus an SBC solution	Contract with the mobile operator
Auto attendant and call queue numbers	Supported	Supported	Supported	User numbers only
Available in the UK?	Yes	Depends on the operator	Yes, with any carrier you can contract	Depends on the operator

The quoted management wording is Microsoft's. The auto attendant row reflects Microsoft's note that Teams Phone Mobile "supports user phone numbers only and doesn't support Audio Conferencing or voice application numbers".

What is a Teams Calling Plan?

A Calling Plan is Microsoft acting as your phone company. Microsoft says PSTN access, phone numbers and support "come from Microsoft, with a 99.999% reliability Service Level Agreement (SLA)".

The UK is a Calling Plan country. Microsoft's Calling Plans page lists a Domestic Calling Plan for organisations in the United Kingdom, an International Calling Plan and a Pay-As-You-Go Calling Plan. On the Domestic and International plans, Microsoft says users in the same country with the same plan "share a pool of minutes", and calls beyond the pool are billed per minute. Pay-As-You-Go users cannot make outgoing calls until the plan is funded.

Suits: small offices that want one supplier, no equipment and simple admin through the Teams admin centre.

Check: whether you need to keep numbers that Microsoft cannot take (see porting below), and what you will pay for calls beyond the pooled allowance.

What is Operator Connect?

Operator Connect lets a telecoms company that has already integrated with Microsoft supply your numbers and calls. Microsoft's Operator Connect planning page describes it as a managed option for when you want PSTN calling "without deploying and maintaining your own Session Border Controllers (SBCs)". You enable the operator in the Teams admin centre and assign its numbers to users.

Microsoft says the operator is responsible for "PSTN connectivity. Telephone number provisioning and porting. Calling services. PSTN-related support and troubleshooting." Microsoft publishes an Operator Connect directory listing participating operators and the countries they cover.

Suits: businesses that want a UK telecoms provider's call rates, support and contract terms with Teams as the phone system, but no SBC to look after.

Check: that the operator is in Microsoft's directory for the UK, who you call when a fault occurs, and how they handle number porting.

What is Direct Routing?

Direct Routing connects any carrier to Teams through a Session Border Controller. Microsoft's Direct Routing planning page says it lets organisations "use existing PSTN carriers, integrate third-party telephony systems, and maintain greater control over their voice infrastructure".

The SBC can be "procured, installed, and managed by you, your integrator, or a Direct-Routing-as-a-Service (DRaaS) provider". Microsoft states that "Only Microsoft-certified SBCs are supported with Direct Routing" and may decline support requests involving non-certified ones.

Suits: businesses that need to keep an existing phone system, analogue devices such as door entry or lift lines, or a carrier that is not in the Operator Connect programme.

Check: who owns and maintains the SBC, whether it is a certified model, and who is accountable when a call fails somewhere between Teams, the SBC and the carrier. Our SIP trunking vs hosted VoIP guide covers the same keep-or-replace question for a traditional PBX.

What is Teams Phone Mobile?

Microsoft's Teams Phone Mobile page says "a user's company-provided, SIM-enabled mobile phone number can also be used as their Teams phone number". It needs a contract with a participating mobile operator and a Teams Phone licence.

Suits: staff who live on their mobile and want one number for Teams and their phone. It cannot provide auto attendant or call queue numbers, so a business with a reception number usually pairs it with one of the other options.

Can I keep my existing UK numbers?

Usually, but the route depends on the option.

Calling Plan: Microsoft's porting guidance says a port "typically takes between 7-14 days" and "might take up to 30 days" depending on your current provider. It also says Microsoft does not currently support transferring UK non-geographic numbers, including 0843, 0844, 0845, 0870, 0871 and 0872. Moving mobile numbers into a Calling Plan is only available in the United States, Puerto Rico and Canada.
Operator Connect and Teams Phone Mobile: the operator handles provisioning and porting.
Direct Routing: the numbers stay with, or move to, the carrier behind your SBC.

Microsoft's advice for any port: "Don't arrange to disconnect the service with your current service provider before submitting your port request." Our keep your business number guide explains the UK porting process in more detail.

Can I mix the options?

Yes. Microsoft says "Multiple PSTN connectivity options can also be used within the same Teams tenant to support different users, locations, and business requirements". A common pattern is Operator Connect or a Calling Plan for most users, with Direct Routing kept only for analogue devices or a legacy phone system.

What about 999 calls?

Microsoft says Calling Plan, Operator Connect and Teams Phone Mobile users "are automatically enabled for emergency calling with the emergency numbers from the country/region based upon their Microsoft 365 or Office 365 usage location". Its dynamic emergency calling guidance says dynamic emergency routing services from these providers are for users in the United States and Canada. For a UK deployment, ask your provider in writing how a 999 call from a laptop or home worker identifies the caller's location, and set emergency addresses for each site.

Worked example: a 15-person office already on Microsoft 365

Picture an office with 15 Microsoft 365 Business Premium users, one main 01 number, a receptionist who runs a call queue, three field staff who mostly use mobiles, and a door entry phone on an analogue line.

Licences: all 15 need Teams Phone Standard (or a Teams Phone with Calling Plan bundle), because Business Premium does not include it.
Main number and call queue: a Calling Plan or Operator Connect can both carry the 01 number on an auto attendant and call queue. The deciding questions are call rates, support and whether you want a UK operator's contract or Microsoft's.
Field staff: Teams Phone Mobile is an option if their mobile operator participates; otherwise they use the Teams app on their phones.
Door entry: this is the one device that might push you to Direct Routing, or to keep it on a separate line or a cellular replacement. Ask the installer what the device supports before deciding.

The output is a short written brief you can give to suppliers, not a price. Add up licences, calls, equipment, support and any SBC service over the same contract term before comparing proposals.

Which option should a small UK business choose?

If your priority is...	Start by comparing
Fewest suppliers and no equipment	Calling Plan
A UK provider's rates and support, no SBC	Operator Connect
Keeping a PBX, analogue devices or a specific carrier	Direct Routing
One number on staff mobiles and in Teams	Teams Phone Mobile, alongside another option

Before you commit, check your broadband can carry the calls. Our guide to how much bandwidth VoIP needs shows how to size the connection, and the PSTN switch-off guide explains why many UK businesses are making this decision now.

Frequently asked questions

Do I need a Teams Phone licence for Operator Connect or Direct Routing?

Yes. Microsoft says Operator Connect, Teams Phone Mobile and Direct Routing each require a Teams Phone licence. Microsoft 365 E5 includes the Phone System capability, so E5 users do not need the separate add-on.

Is Operator Connect better than Direct Routing?

Neither is better in every case. Operator Connect removes the SBC and gives you an operator who handles numbers and support. Direct Routing gives more control and works with any carrier or legacy system, but someone has to run a certified SBC.

Is a Teams Calling Plan available in the UK?

Yes. Microsoft lists the United Kingdom for its Domestic Calling Plan and its Pay-As-You-Go Calling Plan, and offers an International Calling Plan.

Can I move my 0845 number to a Teams Calling Plan?

Not at present. Microsoft says it does not currently support transferring UK non-geographic numbers, including 0843, 0844, 0845, 0870, 0871 and 0872, to Calling Plans. Ask an Operator Connect or Direct Routing provider whether they can host it.

Do I need a Session Border Controller for Teams?

Only for Direct Routing. Calling Plans, Operator Connect and Teams Phone Mobile do not need one on your side.

Related guides

Sources

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