Microsoft Teams can make and receive calls to the regular phone network, but Teams Phone doesn’t connect to the PSTN by itself. You have to pick how those calls reach the outside world, and there are three supported ways to do it: Calling Plan, Operator Connect, and Direct Routing. The licensing for Teams Phone is the same across all three — the difference is who provides the dial tone and how much of the plumbing you run.
The choice matters because it sets your per-minute cost, how much you can customize call routing, whether you need hardware, and how painful it is to keep your existing numbers. Pick wrong and you either overpay for minutes or take on operational work you didn’t need. This guide lays out what each option actually is, where each one fits, and how to decide.
The three options at a glance
Calling Plan vs Operator Connect vs Direct Routing
| Who provides PSTN | Microsoft (Calling Plan) · Your carrier via portal (Operator Connect) · Your carrier/PBX via SBC (Direct Routing) |
|---|---|
| Hardware / SBC needed | None · None · Certified Session Border Controller required |
| Setup effort | Lowest · Low · Highest |
| Routing control | Minimal · Limited · Full (voice routing policies, PBX/analog integration) |
| Carrier choice | Microsoft only · Pick from participating operators · Any carrier that terminates on your SBC |
| Number porting | Port to Microsoft · Stays with the operator · Stays with your carrier |
| Best fit | Small/simple deployments in supported countries · Want carrier choice, no hardware · Complex routing, PBX/analog, unsupported regions |
Calling Plan: buy minutes from Microsoft
Calling Plan is the all-Microsoft route. You assign a Calling Plan to each user, get or port phone numbers through Microsoft, and Microsoft is your phone carrier. There’s nothing to install and no carrier contract to negotiate separately.
It’s the fastest path to live calling, which makes it attractive for smaller organizations or anyone who doesn’t want a telecom relationship to manage. The trade-offs are real, though. Calling Plans are sold per user with monthly minute bundles, and per-minute rates beyond the bundle can be higher than a local carrier would charge. Availability is also limited to the countries where Microsoft sells Calling Plans, so a global org often can’t cover every site this way.
Choose Calling Plan if you’re in a supported country, you want the simplest possible setup, and your call volume is modest or predictable enough that Microsoft’s bundled minutes work out. Be cautious if you have high outbound volume, need countries Microsoft doesn’t cover, or already have a carrier deal that’s cheaper.
Operator Connect: bring a carrier, skip the hardware
Operator Connect is the middle ground that didn’t used to exist. You keep (or choose) a third-party carrier from Microsoft’s list of participating operators, but the integration happens through the Teams admin center — no SBC, no telephony hardware, no PowerShell-heavy provisioning. The operator manages the connection on their side; you assign numbers from a portal.
This gives you carrier choice and often better regional pricing than Calling Plan, while keeping the operational simplicity close to it. Many operators also provide a support relationship and SLAs that Calling Plan doesn’t. The catch is that you’re limited to operators that participate in the program, and you have less routing control than Direct Routing offers.
Choose Operator Connect if you want a specific or local carrier, better per-minute rates, and a support contract, but you don’t want to run hardware. Be cautious if your preferred carrier isn’t in the program, or you need analog device, PBX, or contact-center integration that only Direct Routing handles.
Direct Routing: your telephony, your control
Direct Routing connects Teams to your own telephony — an existing PBX, an analog gateway, a SIP trunk from any carrier — through a certified Session Border Controller (SBC). The SBC is the bridge: it sits between Teams and your provider, handles the signaling and media translation, and is the one hard requirement that the other two options don’t have.
This is the most flexible model and also the most work. With Direct Routing you get full control over voice routing policies, can integrate analog devices (think paging systems, door phones, alarm panels), connect a legacy PBX during a migration, support countries Microsoft and Operator Connect don’t, and tie in compliance recording or contact-center platforms. You can run the SBC yourself or use a provider’s hosted/managed SBC offering.
The cost is operational. You’re responsible for the SBC (or paying someone who is), for certificates, firewall rules, and capacity, and for the routing configuration. When call quality breaks, the troubleshooting surface is larger.
What Direct Routing adds to your plate
- A certified SBC (on-prem, hosted, or a managed/partner service)
- SIP trunk or carrier that terminates on the SBC
- Voice routing policies, dial plans, and PSTN usage records in Teams
- Certificate and firewall management for the SBC
- More layers to check when call quality degrades
Choose Direct Routing if you need analog/PBX integration, an unsupported country, granular routing, or recording and contact-center tie-ins — or you simply want to keep an existing carrier deal. Be cautious if you don’t have the in-house telephony skills and don’t want to pay a partner to run the SBC.
Cost and control: the real trade-off
Strip away the details and the decision is a line from simple-and-fixed to flexible-and-hands-on:
- Calling Plan trades control for simplicity. You pay Microsoft’s rates and accept its routing, but you do almost nothing to run it.
- Operator Connect keeps most of that simplicity while letting you pick a carrier and usually improve per-minute cost.
- Direct Routing gives you the most control and often the best raw minute pricing at scale, but you pay for it in setup and ongoing management.
There’s no single cheapest option. A small office in a supported country may spend the least with Calling Plan because there’s no SBC to run. A high-volume contact center may spend the least per minute with Direct Routing despite the SBC, because the call costs dominate. Run the numbers against your actual volume and region rather than assuming.
Number porting across the three
Keeping your existing numbers is possible with all three, but the number lives in a different place:
- Calling Plan: you port numbers to Microsoft, who then becomes the carrier of record.
- Operator Connect: numbers stay with (or move to) your chosen participating operator.
- Direct Routing: numbers stay with whatever carrier terminates on your SBC.
In every case the porting timeline is driven by the losing carrier and the country’s regulations, not by Teams. Plan the port well ahead of any cutover, and never deactivate old service until the port completes — a botched port is one of the few telephony mistakes that takes your main line down for everyone.
Can you mix them? Yes
These models aren’t mutually exclusive within a tenant. It’s common to run more than one:
- Calling Plan for simple knowledge workers in a supported country.
- Operator Connect for a region where a local carrier is cheaper.
- Direct Routing for a site with a legacy PBX or analog devices that must stay.
Per-user voice routing in Teams makes this practical. A phased migration often starts with Direct Routing alongside an existing PBX, then moves users over time — and some users may never need to move off it.
How to decide by organization type
A quick way to land on a starting point:
Decision guidance by organization
| Small business, one supported country | Calling Plan — least to set up and manage |
|---|---|
| Mid-size org wanting carrier choice, no hardware | Operator Connect — carrier flexibility without an SBC |
| Global org with sites in unsupported countries | Operator Connect where available, Direct Routing to fill gaps |
| Existing PBX or analog devices to integrate | Direct Routing — the only option that bridges them |
| Contact center or compliance recording needs | Direct Routing — for the integration points |
| High outbound minute volume, telephony skills in-house | Direct Routing — best per-minute economics at scale |
If you’re not sure, Operator Connect is the safest default for most organizations past the smallest tier: it gives carrier choice and decent pricing without committing you to running an SBC. Move to Direct Routing only when a concrete requirement — a PBX, an analog device, an unsupported country, a recording platform — forces it.
Wrapping up
Calling Plan, Operator Connect, and Direct Routing all deliver PSTN calling in Teams; they differ in who you buy minutes from and how much you operate. Calling Plan is simplest and all-Microsoft. Operator Connect adds carrier choice with no hardware. Direct Routing gives full control at the cost of an SBC and the work to run it. Match the model to your call volume, region, integration needs, and how much telephony you want to manage — and remember you can mix them per user.
Once you’ve picked a connectivity model and have numbers flowing, the next steps are usually the call-routing features on top: see how to set up an auto attendant in Microsoft Teams and the broader Microsoft Teams guides for the rest of the voice stack.
