The clock is now one of the loudest arguments for moving your PBX to the cloud. BT’s PSTN and ISDN switch-off completes in January 2027, and equivalent transitions are underway across Europe — Germany, the Netherlands and France among them. The lines that have carried business calls for decades are being retired, and every organisation still running an on-premise PBX has a migration decision to make before the dial tone goes quiet.
That deadline has pushed a lot of buyers into a market that has expanded fast. Dozens of cloud PBX providers now compete for the same shortlist, and quality varies more than the marketing suggests. Some are carrier-grade platforms with European data centres and their own numbering; others are thin resellers of someone else’s stack. Telling them apart matters, because a phone system is not a thing you want to re-migrate in eighteen months.
This guide compares the 12 best cloud PBX providers for 2026 — who they suit, how they handle Microsoft Teams and where each one has genuine limitations.
We assessed providers against the criteria that actually matter when you are replacing infrastructure, not just buying handsets:
The best cloud PBX service providers on our list mix global UCaaS platforms with European- and UK-native specialists, because the right answer genuinely depends on your team size, your existing tech stack and where your data has to live. A 40-person firm standardising on Microsoft 365 has different priorities to a 400-seat contact centre with strict data-residency rules. We’ve flagged who each of these hosted PBX providers actually suits rather than pretending one wins outright.
Best for: Feature-rich, AI-heavy cloud PBX for mid-market and enterprise.
RingCentral is the closest thing the market has to a default benchmark. Its RingEX platform (formerly MVP) bundles voice, messaging, video and fax with one of the deepest feature sets and integration libraries available, and 2026 has seen an aggressive push into call and conversation AI. It suits mid-to-large, multi-site organisations that value breadth and reliability over the lowest sticker price.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing (plus an embedded Teams app).
Best for: Businesses that want unified UCaaS and contact centre on one platform.
8x8 pairs a hosted PBX with a full contact centre on a single platform, with unusually wide international PSTN coverage. It is a strong fit for mid-market and enterprise buyers who need both a phone system and customer-facing queues, and for multinationals replacing on-premise lines across several countries. It is also the only provider offering a Microsoft-certified Teams contact centre over Operator Connect.
Key strengths
Potential limitations
Microsoft Teams integration: Operator Connect (certified) plus Direct Routing.
Best for: Organisations already standardised on Microsoft 365.
For businesses that already run everything through Teams, Microsoft Teams Phone turns that same app into the phone system — no second client to deploy. PSTN connectivity comes three ways: Microsoft Calling Plans, Operator Connect, or Direct Routing through your own carrier. It is the default choice for Microsoft-first estates and competes on bundling and familiarity rather than telephony depth.
Key strengths
Potential limitations
Microsoft Teams integration: Native — it is Teams.
Best for: UK channel-led businesses
Gamma is one of the UK’s largest UCaaS and SIP players, and its Horizon hosted PBX is a mainstay for UK businesses — usually bought through one of its 1,500+ partners rather than direct. It runs on its own carrier-grade UK network and offers both routes to Microsoft Teams voice, with a growing European footprint through its STARFACE acquisition in Germany.
Key strengths
Potential limitations
Microsoft Teams integration: Operator Connect plus Direct Routing (“Horizon for Teams”).
Best for: European businesses that put EU data residency first.
NFON is a pan-European cloud telephony specialist operating across roughly 15 countries, with its flagship Cloudya service. It positions squarely on European trust — EU infrastructure, GDPR by design and TÜV-certified voice quality — and mainly serves SMB and mid-market buyers who want a straightforward, feature-rich hosted PBX rather than a sprawling collaboration suite.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing, plus a Cloudya app inside Teams.
Best for: Service Providers building or expanding a cloud PBX portfolio.
Dstny sits at a different layer of this list. Rather than selling a phone system directly to end businesses, it is the European Always-On Communications platform that powers cloud communications for 200+ service providers across 80+ markets, reaching 5M+ users. Its stack spans carrier-grade voice with mobility at the core (fixed-mobile convergence), native Microsoft Teams connectivity through Dstny Call2Teams, conversation and CRM analytics, and AI agents — all white-label and built European-by-design. If you buy cloud communications from a local operator, there is a good chance Dstny is the infrastructure underneath.
Key strengths
Microsoft Teams integration: Native (Dstny Call2Teams — Direct Routing and Operator Connect).
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Best for: Regulated enterprises and existing Cisco estates.
Webex Calling is Cisco’s enterprise-grade cloud PBX, strongest in large Cisco shops and regulated industries where security, compliance and data residency are non-negotiable. It offers flexible PSTN options and one of the best-documented UK and EU data-residency stories in the market, tied into the wider Webex suite of meetings, messaging and contact centre.
Key strengths
Potential limitations
Microsoft Teams integration: Embedded “Cisco Call for Microsoft Teams” app (not Direct Routing / Operator Connect).
Best for: Organisations already using Zoom Meetings.
Zoom Phone extends the Zoom platform into telephony, and for the millions already on Zoom it is a natural consolidation play. It offers flexible metered or unlimited plans by region, seamless escalation from call to meeting, and — usefully for cost-conscious buyers — some of the more transparent UK pricing on this list. It scales from SMB to enterprise, with BYO carrier options for larger deployments.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing (plus an embedded Zoom app).
Best for: Businesses that want a phone system plus programmable comms APIs.
Now part of Ericsson, Vonage combines a hosted PBX (Vonage Business Communications) with a best-in-class programmable communications API business. That makes it a strong pick for organisations that want a reliable phone system and the ability to embed voice, video or messaging into their own apps and workflows. It publishes transparent UK per-user pricing with a low entry point.
Key strengths
Potential limitations
Brand momentum has been somewhat diluted since the Ericsson acquisition.
Microsoft Teams integration: Direct Routing (embedded integration plus a simpler voice-in-Teams option).
Best for: Sales and customer-facing teams wanting a browser-native system.
Wildix is a genuinely European, partner-led UCaaS platform built entirely on WebRTC — telephony, chat, video and web chat all run in the browser with no plugins. It targets sales-driven SMB and mid-market organisations and differentiates on a single unified stack, security-by-design and built-in AI, sold and implemented exclusively through local partners.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing via teams4Wildix (no Operator Connect).
Best for: Teams that want AI built into every call.
Dialpad is the AI-native option on this list. Real-time transcription, sentiment analysis, live agent assist and call summaries are built into every call rather than sold as an add-on, on a single platform spanning phone, video, messaging and an AI contact centre. It is well-funded, quick to set up, and increasingly present in the UK and Europe, with a core following among sales and support teams.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing (via an embedded Teams app; requires Teams Phone licensing).
Best for: Cost-conscious businesses
3CX is a software PBX rather than a carrier — you bring your own SIP trunks and numbers and deploy it on-premise, self-host it in your own cloud tenant, or let 3CX host it. Its flat, per-system licensing (based on simultaneous calls, not users) appeals to organisations that want to avoid per-seat SaaS fees and keep full control of where their voice data lives. It is popular with SMBs and MSPs across Europe.
Key strengths
Potential limitations
Microsoft Teams integration: Direct Routing on higher editions (Teams users become 3CX extensions).
A traditional on-premise PBX (private branch exchange) is the box in the comms room that routes calls inside your business and connects them to the outside world — handling extensions, call transfers, voicemail, hunt groups and IVR menus. A cloud PBX takes exactly that functionality and moves it to a provider’s hosted infrastructure, delivered over the internet as a managed service.
For the person making and receiving calls, almost nothing changes: they still dial, transfer and pick up as before, whether from a desk phone, a softphone on their laptop or a mobile app. What changes is everything behind the scenes. There is no hardware to buy, patch or replace; capacity scales up or down in an admin portal; updates and redundancy are the provider’s responsibility; and staff can work from anywhere with a connection. In practice, a cloud PBX system turns a capital purchase and an ongoing maintenance burden into a predictable per-user subscription. Providers deliver these cloud PBX services from redundant data centres, and a cloud PBX phone system brings desk, desktop and mobile together under one business identity.
The terms overlap. A cloud based PBX and a hosted PBX system describe the same idea — PBX features delivered from a provider’s data centre rather than your building. Some vendors also market themselves as virtual PBX providers, which is the same concept again. The distinction that does matter is architectural, and it is the subject of the next section.
“Hosted” and “cloud” are used interchangeably in everyday conversation. Where vendors distinguish them, “cloud” usually implies multi-tenant SaaS — many customers sharing elastic infrastructure — while “hosted” can mean a dedicated instance managed on your behalf. For most buyers the practical difference is small; the questions that matter are where your data sits, how the platform scales and who maintains it.
The migration to hosted PBX solutions is no longer optional for most organisations — it is being scheduled for them. In the UK, BT is retiring the PSTN and ISDN networks, with the switch-off completing in January 2027; new analogue and ISDN lines have already stopped being sold. Across Europe, incumbents are running parallel transitions, with Germany largely complete, the Netherlands well advanced, and France and others following.
This is a genuine deadline rather than a scare tactic, and many businesses have been slow to act. The reassuring part is that cloud PBX is the natural migration path: you keep the same business phone numbers, retain the same core functionality, and remove the on-premise hardware entirely. Moving before the deadline — rather than in the rush just before it — gives you time to port numbers cleanly, train staff and choose the right provider instead of the first available one.
A cloud PBX for business is a mature, proven technology, not an experiment — and the market is genuinely competitive. The right cloud PBX solution depends on your existing stack, your team size and your geographic and compliance requirements. Microsoft-first estates will gravitate toward Teams Phone; regulated enterprises toward Cisco or a strongly European provider; sales teams toward AI-native platforms; and UK businesses will find real strength in home-grown networks. The PSTN switch-off has turned this from a someday project into a near-term decision with a firm date attached.
Wherever you land, verify current company status and pricing before you commit — this is a market that consolidates fast. And if you are on the other side of the table, building rather than buying, the platform underneath many of these services is worth a closer look.
In everyday use they mean the same thing: PBX functionality delivered from a provider’s data centre rather than hardware in your office. Where vendors draw a line, “cloud” tends to imply multi-tenant, elastic SaaS, while “hosted” can mean a dedicated instance managed for you. For most buyers the distinction rarely affects the decision — data residency, scalability and support matter more.
Yes. Most providers connect to Teams through Direct Routing or Operator Connect, and Microsoft Teams Phone adds calling natively inside Teams itself. Confirm which model a provider supports, as the admin effort and carrier flexibility differ between them.
Calls route over your internet connection, so a good provider builds in resilience: automatic failover to 4G/5G or mobile, call forwarding to another number, and redundant data centres. Check the SLA and ask specifically what happens during an outage before you sign.
Anywhere from a few days for a small single-site business to several weeks for a large, multi-site deployment. Number porting can take a couple of weeks — so start early, especially ahead of the PSTN switch-off.
It is arguably where cloud PBX shines. Every site sits on one platform with free on-net calling between locations, centralised administration and consistent features regardless of where staff are working.
You keep them. Number porting lets you move existing geographic and non-geographic numbers to a new provider. Confirm porting timescales and any fees up front, and never cancel your old service until the port has completed.