If you are setting up Microsoft Teams Phone and want users to make and receive calls to and from external numbers, you have three options. Most comparisons only cover two of them. Understanding all three - and what they actually cost and require - is the difference between a smooth deployment and one that comes back to bite you six months later.

Key takeaways:

  • Calling Plans - Microsoft acts as your carrier. Simple, limited to roughly 35 countries, approximately $21/user/month. Right for small teams with straightforward needs.
  • Direct Routing - connect Teams to any carrier via a Session Border Controller. Full control, global coverage, cheaper at scale, but complex to set up and maintain.
  • Operator Connect - a third option most guides skip. Microsoft-certified carriers manage the infrastructure for you. No SBC required. Increasingly the preferred choice for mid-market businesses.
  • SBC complexity - Direct Routing setup takes weeks to months. Ongoing management requires VoIP/SIP expertise. Small businesses without in-house telecoms skills often underestimate this.
  • Operator Connect is rapidly becoming the mid-market standard and is worth evaluating before defaulting to Direct Routing.

The Three Ways to Make External Calls from Teams

Microsoft Teams Phone is the licence that enables telephony features within Teams. On its own, it cannot make or receive PSTN calls (calls to standard phone numbers). To connect Teams to the outside world, you need one of three PSTN connectivity options:

  1. Microsoft Calling Plans - Microsoft is your carrier
  2. Direct Routing - you bring your own carrier, connected via an SBC
  3. Operator Connect - a Microsoft-certified carrier connects directly through Teams Admin Center, managing the infrastructure on your behalf

Each option has different licensing requirements, setup complexity, cost profiles, and geographic coverage. The right choice depends on your business size, location, call volume, and IT resource.

Microsoft Calling Plans: Simple, Bounded, and Often Misunderstood

Calling Plans are the lowest-friction route to Teams Phone. Microsoft acts as your telecoms carrier, provides the phone numbers, and bundles call minutes per user per month. Setup happens entirely within the Teams Admin Center - no external vendors, no hardware, no SIP configuration.

Pricing starts at approximately $21/user/month for a domestic calling plan, with Domestic and International bundles available at higher price points. Each user requires both a Teams Phone licence and a Calling Plan licence on top of their Microsoft 365 subscription.

The simplicity is real and worth something. For a 10-person UK or US office that needs basic inbound and outbound calling, this is a working setup in hours, not weeks.

Where Calling Plans Fall Short

The limitations become material quickly:

  • Country availability is restricted to around 35 countries. If your business operates outside supported regions, Calling Plans are not an option.
  • PBX functionality is basic - voicemail, call hold, and call transfer work. Complex call routing, hunt groups, call centres, and compliant call recording are limited or unavailable.
  • Number porting from an existing carrier is described by multiple IT admins as "challenging" and slow.
  • Cost scales poorly - international calls consume minutes bundles fast, and adding users adds per-user licensing costs at Microsoft's carrier rates, which are not the most competitive in the market.
  • No carrier choice - you are locked into Microsoft as your provider. If you have an existing carrier relationship or preferred SIP trunk provider, Calling Plans require abandoning it.

Calling Plans are right for small teams (under 50 users) in a single supported country with simple telephony requirements and limited IT resource. Beyond that, the case for an alternative gets stronger quickly.

Direct Routing: Full Control, Real Complexity

Direct Routing lets you connect Microsoft Teams Phone to any telecoms carrier of your choice, via a certified Session Border Controller. You are not reliant on Microsoft as a carrier. You can use an existing SIP trunk, keep a preferred carrier relationship, and configure call routing with full flexibility.

The benefits are significant:

  • Global coverage - not restricted to Microsoft's supported country list
  • Integration with on-premise or hybrid PBX systems
  • Support for analog devices, contact centres, and compliant call recording
  • Typically lower per-minute costs than Calling Plans at high volumes
  • Long-term total cost of ownership is usually lower for businesses with 100+ users or high call volumes

The trade-off is complexity. Direct Routing is not a self-service option. It requires an SBC, a third-party telecoms provider, and expertise to configure and maintain the setup.

What an SBC Is (and What It Costs)

An SBC (Session Border Controller) is the component that sits between Microsoft Teams and your external carrier. It handles protocol translation, call routing, security, and media handling between the Teams environment and the public telephone network.

SBCs come in two forms:

  • On-premise SBC - a physical appliance or virtualised instance running in your own data centre or server room. Higher upfront hardware cost (several thousand pounds or dollars), plus internal management overhead. Suitable for large enterprises with existing data centre infrastructure.
  • Hosted/cloud SBC - managed by a third-party provider as a subscription service. No hardware to buy or maintain. Typical pricing from managed providers is around $25/user/month, though this varies significantly. Faster to deploy and more practical for businesses without dedicated server infrastructure.

Regardless of deployment model, Direct Routing setup takes a minimum of two to three weeks for a straightforward cloud SBC configuration. Complex multi-site or multi-country deployments can take several months. Ongoing management includes monitoring call quality, renewing certificates, and updating routing policies - tasks that require VoIP and SIP expertise.

Microsoft provides no support for your carrier-side issues under Direct Routing. When a call fails, the diagnostic trail runs through your SBC and your provider, not through Microsoft support.

Operator Connect: The Option Most Comparisons Miss

Operator Connect is a newer connectivity model that sits between Calling Plans and Direct Routing in both complexity and flexibility. A Microsoft-certified telecoms carrier connects directly to your Teams environment through the Teams Admin Center. The carrier manages the SBC and the infrastructure on your behalf - you do not need to deploy or maintain one yourself.

From a setup perspective, Operator Connect is significantly faster than Direct Routing. Phone numbers can be assigned through the same Teams Admin Center interface, and the certified operator provides proper support SLAs - which Calling Plans (via Microsoft support tickets) often cannot match.

From a cost perspective, Operator Connect is typically slightly cheaper than Direct Routing overall, because you are not paying separately for SBC management. It is more expensive than Calling Plans in most cases, but the carrier rates are usually more competitive than Microsoft's bundled minutes.

The limitation is carrier choice: you are restricted to Microsoft-certified Operator Connect partners. This is a growing list, but it is not unlimited, and if your preferred carrier is not certified, Operator Connect is not available for that relationship.

Operator Connect is rapidly becoming the standard for mid-market businesses in the 100-500 user range. It provides carrier flexibility and better SLAs than Calling Plans, without requiring the internal telecoms expertise that Direct Routing demands.

Cost Comparison

Comparing costs directly is difficult because pricing varies significantly by region, carrier, call volume, and contract. The following is a practical guide to relative cost profiles.

Option Typical cost Setup time Carrier choice SBC required
Calling Plans ~$21/user/month Hours None (Microsoft) No
Operator Connect Varies by carrier Days Microsoft-certified partners No
Direct Routing (hosted SBC) ~$25+/user/month 2-4 weeks Any Yes (managed)
Direct Routing (on-premise SBC) Variable Weeks to months Any Yes (self-managed)

Real-world bills for all options run higher than the advertised per-user rate once Microsoft 365 base licences, Teams Phone add-ons, and regional regulatory fees are included.

For businesses under 50 users with low international call volume, Calling Plans are cost-competitive. Above that threshold, or with significant international calling, the economics shift towards Operator Connect or Direct Routing.

Which Option Suits Which Business

Choose Calling Plans if:

  • You have under 50 users in a single supported country
  • Telephony requirements are basic - inbound/outbound calls, voicemail, basic transfer
  • You have minimal internal IT resource and want Microsoft to manage everything
  • You are already paying for Microsoft 365 and want to add calling with minimum additional complexity

Choose Operator Connect if:

  • You have 100-500 users or operate across multiple countries
  • You want carrier choice without managing an SBC
  • You need better call quality SLAs than Microsoft support provides
  • Your IT team is competent but does not have specialist VoIP/SIP expertise

Choose Direct Routing if:

  • You have 500+ users or complex multi-site infrastructure
  • You have existing PBX systems, analog devices, or specialist call centre requirements
  • You have a preferred carrier contract you want to retain
  • You have in-house VoIP/telecoms expertise or a managed service partner to handle the SBC
  • You operate in countries where Calling Plans and Operator Connect are not available

Frequently Asked Questions

Q: What is the difference between Microsoft Calling Plans and Direct Routing? Calling Plans make Microsoft your carrier - they supply the phone numbers and call minutes for a fixed monthly fee per user. Direct Routing lets you use any carrier by connecting Teams to your provider via a Session Border Controller. Direct Routing is more complex, more flexible, and typically cheaper per call at scale.

Q: Do I need an SBC for Microsoft Teams Direct Routing? Yes. A Session Border Controller is required for all Direct Routing deployments. It acts as the bridge between Microsoft Teams and your external carrier. You can either host an SBC on your own infrastructure or use a managed/hosted SBC from a provider, which is typically faster to deploy and requires less internal expertise.

Q: What is Operator Connect and how is it different from Direct Routing? Operator Connect is a Microsoft programme where certified telecoms carriers connect directly to your Teams environment without requiring you to manage an SBC. The carrier handles the infrastructure. It offers more carrier flexibility than Calling Plans and less complexity than Direct Routing, making it a practical middle ground for mid-market businesses.

Q: How much does Microsoft Teams Direct Routing cost? Direct Routing costs combine your Microsoft Teams Phone licence, the SBC (hardware or hosted service, typically around $25/user/month for managed), and your carrier's per-minute or SIP trunk charges. Total costs vary significantly by provider and call volume. For high-volume users, per-minute rates through a chosen carrier are usually materially cheaper than Microsoft's bundled Calling Plan minutes.

Q: Can I port my existing phone numbers to Microsoft Teams? All three options support number porting, but the experience varies. Calling Plan number porting is handled by Microsoft and is widely reported as slow. Operator Connect and Direct Routing both use your carrier's porting process, which is typically faster and more predictable. If retaining existing numbers quickly is important, avoid Calling Plans.

Q: Which option is best for a small UK business using Microsoft Teams? For a small UK business (under 50 users, basic telephony needs), Calling Plans are the simplest starting point. For businesses needing better carrier rates, more flexibility, or stronger support SLAs, Operator Connect with a UK-based certified carrier is the more practical choice. Direct Routing is generally not warranted unless you have an existing PBX investment to protect or a complex multi-site requirement.

The decision between these three options is primarily a question of how much control you need and how much complexity you can absorb. Calling Plans trade flexibility for simplicity. Direct Routing trades simplicity for control. Operator Connect sits between them and is underrepresented in most vendor comparisons - which typically have a reason to steer you towards one of the other two.

If you are evaluating Teams Phone for the first time, model the cost against your actual call volume, check whether your preferred carrier is Operator Connect-certified, and be realistic about your internal capacity to manage an SBC before committing to Direct Routing.