Microsoft Teams Phone: Calling Plans, Operator Connect or Direct Routing?
If your organisation already runs Microsoft 365 and lives in Teams, using it as the phone system is an obvious thought. Teams Phone makes that possible — but "Teams Phone" is not one product. It is a capability that can be connected to the public telephone network three different ways, and the choice determines your costs, your flexibility and, crucially, who you call when calls stop working.
The three options
Microsoft Calling Plans
Microsoft is your carrier. You buy a Teams Phone licence plus a calling plan, and Microsoft provides the numbers and the minutes.
Good when: you are in a country Microsoft serves well, your requirements are standard, and you value one vendor and one bill above everything else.
Constraints: country availability is uneven, number porting runs through Microsoft's process at Microsoft's pace, and per-user pricing with bundled minutes rarely suits organisations with uneven calling patterns. There is limited room to negotiate rates.
Operator Connect
A participating carrier provides the telephony, but the integration is managed through the Teams admin centre. You pick an operator from a list inside the portal, and the connection is established without you building anything.
Good when: you want a carrier relationship — better rates, local presence, a named account team — without running infrastructure. For most mid-sized organisations this is the sensible middle.
Constraints: you choose from participating operators in your region. Capability varies by operator, so compare the specific one rather than the model.
Direct Routing
You connect your own Session Border Controller (SBC) to Teams and bring your own carrier. Maximum control, maximum responsibility.
Good when: you have an existing PBX to coexist with, analogue devices to support, call flows that need handling outside Teams, contact centre integration, or regulatory requirements about where media flows. Also the usual answer where Microsoft's calling plans are unavailable.
Constraints: you own an SBC — certified hardware or a virtual appliance — and you own its configuration, certificates, patching and monitoring. When calls fail, the diagnosis is yours.
The question that actually decides it
Not price. Who do you want to call at 9am when calls are failing?
With Calling Plans, that is Microsoft. With Operator Connect, your operator, who has a supported integration path. With Direct Routing, it is you first — your SBC, your certificates, your trunk — and only then whichever vendor you can demonstrate is at fault.
That is a real operational commitment, and it is the factor most often underweighted in the comparison. Direct Routing is the most capable option and the one that requires you to have, or buy, the expertise to run it.
Where projects go wrong
Expecting feature parity with a traditional PBX
Teams Phone is excellent at person-to-person calling and integrates beautifully with the rest of Microsoft 365. It is not a full PBX replacement for every scenario. Complex hunt-group behaviour, sophisticated queueing, paging, intercom and some analogue device support are weaker or need additional products.
Inventory your current call flows before committing. The ones that will not translate are better found during design than during cutover.
Forgetting analogue devices
Fax machines, alarm panels, lift phones, door entry and card terminals do not become Teams endpoints. Direct Routing with an SBC that has analogue ports, or a retained small gateway, is the usual answer. Find them during inventory.
Underestimating the licensing
Teams Phone is a licence per user, on top of Microsoft 365. Calling plans are additional. Audio Conferencing may be separate depending on your tier. Common area phones, meeting rooms and auto attendants each have their own licensing treatment.
The total is frequently higher than the per-user comparison suggests. Model it with your actual user mix — not everyone needs the same licence — before deciding on price.
Treating the network as someone else's problem
Teams carries media directly between clients where it can. That makes local network quality, QoS and firewall configuration decisive for call quality. The most common cause of "Teams calls sound bad" is not Teams; it is a network that was never configured for real-time traffic.
Run Microsoft's network assessment before deployment, not after the complaints.
Emergency calling
Teams Phone has specific configuration for emergency addresses, dynamic location for roaming users, and security desk notification. It is not automatic. Configure it deliberately, and test it — this is a legal obligation under Kari's Law and RAY BAUM'S Act, not a nice-to-have.
When Teams Phone is not the right answer
It is worth saying plainly, because the integration pull is strong:
- Contact centre operations. Teams Phone is not a contact centre. There are certified solutions that layer on, but if queue management, workforce planning and supervisor tooling are central to your business, evaluate purpose-built platforms properly rather than assuming Teams plus an add-on will suffice.
- Heavy call-flow complexity. Multi-level IVR with sophisticated routing is not Teams' strength.
- Organisations not standardised on Teams. The whole benefit is that calling lives where people already work. If half the business lives elsewhere, that benefit evaporates and you are comparing on telephony merit alone.
A sensible evaluation order
- Inventory every number, device and call flow, including the analogue ones.
- Identify which flows Teams handles natively and which need something else.
- Run the network assessment.
- Model licensing against your real user mix.
- Decide the connectivity model from the operational question — who you call when it breaks.
- Pilot with one team, including a full emergency-calling test.
- Then plan the migration.
Most disappointing Teams Phone projects skipped steps one and three. The platform is capable and the integration is genuinely good; the failures are nearly always requirements that were never written down, discovered after the old system was gone.
