The Best Business Phone Lines in the UK

Choosing the best business phone line is a must if you want to bridge the gap between your team, business partners, and clients. However, with the UK’s PSTN and ISDN networks set to be switched off in January 2027, British businesses must migrate to a Voice over Internet Protocol (VoIP) provider to continue making and receiving calls.

To identify the strongest options, we assessed leading VoIP providers using Expert Market’s in-house research framework, which looks at pricing transparency, call quality, and core features. We found that RingCentral Ultimate to be the strongest all-around phone line for most businesses, while 8×8’s Unified Communications plan performed particularly well for teams that need generous or unlimited calling allowances.

The deadline to change your landline provider may be fast approaching, but don’t worry — we’re here to help. Below, we go through our top-rated VoIP phone line plans, detailing what businesses they are best suited to and why. We’ll also clarify how VoIP business phone lines compare with the traditional landline networks, and explain what the future holds for them.

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The Best Business Phone Lines for UK Businesses

To keep their communication lines running, UK-based businesses need to transfer their business phone line to a VoIP phone line before the ‘Big Switch Off’ of UK landlines in January 2027. However, 77% of UK businesses haven’t yet made preparations to migrate to digital phone systems, highlighting how many businesses may still need to act ahead of the 2027 deadline.

Click here to jump to our guide to the differences between VoIP and traditional landlines, or read on below for mini-reviews on our favourite VoIP providers.

1. RingCentral Ultimate: Best Overall Business Phone Line Supplier Plan

Our extensive research shows that RingCentral Ultimate is the strongest all-round business phone system available in the UK for organisations with advanced communication needs.

It builds on RingCentral’s core VoIP functionality with enterprise-grade features designed for larger teams, contact-centre environments, and businesses that rely heavily on analytics, automation, and omnichannel communication.

What do we like about RingCentral Ultimate?

RingCentral Ultimate delivered top-tier results across our testing, particularly in advanced call handling, analytics, and multichannel communications.

It offers one of the most comprehensive feature sets on the market, combining sophisticated call management tools — such as intelligent call routing, call recording, and advanced interactive voice response (IVR) — with powerful analytics, SSO support, and omnichannel capabilities spanning voice, video, SMS, and team messaging.

These features make RingCentral Ultimate especially well-suited to larger teams and customer-facing organisations that need deeper insight, tighter controls, and greater flexibility than entry-level VoIP plans can provide.

RingCentral Ultimate also seamlessly integrates with Salesforce and over 107 other CRM, helpdesk, workspace, email, and conferencing software. Uniquely, compared with the other providers we tested, it also integrates with customer live chat channels like WhatsApp, and it’s the only one to support initiating video calls via Microsoft Teams.

Crucially for businesses with high employee turnover, it also scored superbly for its range of training features, alongside 8×8 Unified Communications and Vonage Max. We found it could do it all, from recording calls and creating transcripts to live call monitoring, whispering, and call barging functionality.

Where could RingCentral Ultimate be improved?

RingCentral Ultimate isn’t built for outbound-heavy sales or marketing teams. It doesn’t include advanced dialling features like power or predictive dialling as standard, which limits its suitability for large-scale outreach.

To access these tools, businesses need a separate contact-centre product from RingCentral, such as RingCX or Engage Voice, at an additional cost.

If you need unlimited minutes, see the details on 8×8’s Unified Communications package below.

Is RingCentral Ultimate right for your business?

Overall, RingCentral Ultimate is well-suited to large-scale communications and improving customer service at medium-sized enterprises, such as healthcare (where it also took the top prize). Specifically, the VoIP plan is ideal for the following types of enterprises.

✅ Best for businesses that need:

• CRM integrations with major platforms: Seamless connections with tools like Salesforce, HubSpot and Zendesk.
• Training and call visibility: Advanced coaching and performance tools, such as call whisper, barge, monitoring, and a real-time dashboard to support call quality and staff development.
• Scalable team communications: A robust suite of unified communication tools — including voice, messaging and video — supports growing hybrid or remote teams with multiple channels.

2. 8×8 Unified Communications: Best For Businesses With High International Call Volumes

While RingCentral Ultimate remains a standout all-rounder, 8×8’s Unified Communications plan matches it closely across most core VoIP features — and in one key area, it pulls ahead: truly unlimited calling minutes.

This makes 8×8 Unified Communications a particularly strong option for businesses that handle consistently high inbound and outbound call volumes, where minute caps or fair-use limits could otherwise drive up costs. Specifically, customer support teams and sales-led organisations are likely to benefit most from the plan’s unlimited calling and global reach.

What do we like about 8×8 Unified Communications?

The 8×8 Unified Communications plan performed exceptionally well on most bases, earning a score of 4/5 or higher in seven of our eight test areas. It performed particularly well due to its comprehensive training features, such as advanced tools like call barge and whisper, that match RingCentral Ultimate in terms of extent and variety.

Its help and support options are also to be commended, with 8×8 supplying 24/7 live chat support, an email and phone customer team, plus an online knowledge base and user forum to help you through any problems you might encounter.

Where could 8×8 Unified Communications be improved?

The main area where 8×8 Unified Communications performed below par was in its bespoke pricing. You’ll have to contact 8×8’s sales team directly for a quote, which we found a little unclear for potential customers.

And from what we do know about its Unified Communications plan pricing, affordability is not 8×8’s strong suit: it’ll set you back around £36 per month when paying annually, according to our estimates. This saw 8×8 United Communications get one of the worst scores in terms of affordability.

Still, if you can match its monthly price, you’ll have a lot more features to play with than many other business phone providers.

The only other area where RingCentral Ultimate had it beaten was around software integrations. 8×8 Unified Communications doesn’t support live chat integration, meaning businesses that regularly use this functionality should look elsewhere.

Is 8×8 Unified Communications right for your business?

Given that it supports unlimited calling to 48 countries and has excellent support for internal communication via multiple channels, any businesses with global and international operations will find 8×8 Unified Communications a strong candidate.

✅ Best for businesses that need:

• Unlimited international calling: Seamless calling to 48 countries makes it ideal for organisations with global operations or frequent cross-border communication.
• Strong internal communication support: Multi-channel tools (voice, messaging, and video) help distributed teams stay connected and productive across locations.
• Remote-friendly training and coaching: Advanced training features — including call monitoring, barge, and whisper — allow managers to coach and develop staff effectively, even in remote environments.

3. GoTo Connect Phone System: Best For Businesses With Existing Desk Phone Hardware

Our research shows that GoTo Connect Phone System is another top business phone line plan. But one group of businesses should be interested in particular: those that already have existing phone hardware.

GoTo Connect integrates with over 10 desk phone brands, which is more than any other provider we tested, especially VoIP solutions with lacklustre integration options like bOnline. Here’s a brief look at why else the VoIP plan could be for you.

What do we like about GoTo Connect Phone System?

We awarded the GoTo Connect Phone System plan a perfect score for both desk phone compatibility and built-in communication channels.

On the hardware side, the Phone System plan supports a wider range of desk phone manufacturers than any other VoIP plan we tested. This gives businesses far more flexibility to reuse existing handsets or choose the exact phone brand that suits their setup, rather than being locked into a short list of approved devices.

The plan also stands out for its breadth of included communication tools. Unlike many VoIP plans that treat messaging, faxing or video as paid add-ons, the GoTo Connect Phone System brings team messaging, e-fax, and audio and video conferencing for up to 250 participants together in one unified platform.

For teams that want voice calling to sit alongside modern collaboration tools — without juggling multiple systems — this makes the Phone System plan a particularly strong all-in-one option.

It even goes above and beyond as one of the few providers to support outbound SMS campaigns and is aided by AI-assisted personalisation and a multi-channel shared inbox to keep track of messages.

In comparison, VoIP plans like bOnline Unlimited Calling and Vonage Max lack centralised messaging options. This makes GoTo Connect Phone System a much better option for teams that rely on SMS for customer communication at scale, such as sales teams, appointment-based businesses and customer support desks that need visibility across conversations.

Where could GoTo Connect Phone System be improved?

The GoTo Connect Phone System plan has a more limited set of CRM integrations and training tools than some rival VoIP plans. While it supports Salesforce and selected API integrations, it lacks compatibility with platforms such as Microsoft Teams.

Training features are also fairly basic — call monitoring and recording are included, but advanced coaching tools like call whisper or call barge are not.

As a result, the Phone System plan may be less suitable for rapidly scaling customer support teams or organisations with complex, software-driven workflows. In these cases, plans from 8×8, RingCentral or Vonage Max may offer greater depth.

The plan also includes fewer built-in security controls than some competitors, with no multi-factor authentication and more limited user permissions. This could be a drawback for businesses that handle sensitive data or require stricter access management.

Is GoTo Connect Phone System right for your business?

It should be clear that GoTo Connect Phone System is a solid choice for businesses that already own an extensive amount of desk phones due to its high compatibility with various phone brands (although, do always check your brand is compatible before purchasing).

Read on for a more detailed breakdown of who GoTo Connect Phone System is best suited for.

✅ Best for businesses that need:

• Strong desk phone compatibility: Broad support for third-party desk phone brands makes it ideal if you already have handsets (or want the flexibility to choose your preferred hardware).
• All-in-one communications: Voice calling plus video meetings, team messaging and SMS in one platform helps keep internal comms tidy — especially across remote or multi-site teams.
• Reliable call handling for busy teams: Practical features like IVR, ring groups, call routing, and queues support customer-facing teams that need calls to reach the right person quickly.

4. Vonage Max: Best For Small Businesses With High Domestic Call Volumes

Vonage Max is our best phone line provider for small businesses since it provides excellent third-party integrations at a reasonable price. Here’s what you need to know about Vonage Max before we jump into the nitty gritty.

What do we like about Vonage Max?

Helping to improve the skill set of your staff, we found Vonage Max’s training features matched our two leading business phone providers RingCentral and 8×8.

You’ll get call recording, monitoring, barging and whisper functionality, plus analytics and reporting tools, all included to ensure new hire and existing staff productivity and proficiency keep at pace with your business needs.

There’s also some well-equipped call management tools. Staff can feel empowered to perform all the actions they need to with handy outbound communication features, whether that’s screening live calls via caller ID or after missed ones via voicemails, re-routing audio or video calls, or setting up custom call lists to reach out to select customers, more quickly.

And when considering the bottom line, Vonage Max is a strong contender, too. At £25 per user, per month, it provides enough advanced features to warrant that price, including plenty of CRM integrations and unlimited inbound/outbound minutes which some providers struggle to match.

Overall, only bOnline beat it in for value. However, bOnline is cheaper than Vonage, but also less robust, in our view.

Where could Vonage Max be improved?

While Vonage Max integrates with major CRM systems and productivity tools, like Salesforce and HubSpot, its potential amount and variety of software integrations do not match its rivals.

Namely, we couldn’t fully integrate Vonage’s most expensive plan with any video conferencing or customer-service live chat apps. This could limit its utility for businesses with more extensive or complex software needs, even if calendar apps like Office 365 and Google Workspace are supported.

We weren’t overly impressed by Vonage Max’s communication tools either. While there’s support for messaging and video conferencing, which may be enough for some businesses, a lack of SMS or e-fax functionality could be a missing ingredient for others.

Is Vonage Max right for your business?

Overall, Vonage Max is best suited to small and growing UK businesses that want a flexible, easy-to-manage VoIP plan with strong call handling and unlimited minutes — all without long-term contracts or complex commitments.

✅ Best for businesses that need:

• Flexible, no-contract pricing: Month-to-month billing makes it ideal for first-time VoIP users or businesses that want to avoid locking into long contracts.
• Unlimited calling: Unlimited inbound and outbound UK calling helps small teams handle high call volumes without worrying about per-minute charges.
• Strong call management tools: Useful features like call routing, screening, call recording and voicemail help customer-facing teams stay responsive.

5. bOnline Unlimited Calling: Best For Cost-Conscious Businesses Switching From Landlines

For a budget-priced business phone line that does the basics extremely well, bOnline Unlimited Calling is unquestionably our favourite option. Take a look at its scorecard below to get an idea of what its strong suits are.

What do we like about bOnline Unlimited Calling?

Prioritising affordability, whilst still offering core call management and communication functionalities like call routing, ring groups, and integrations with popular CRM and helpdesk applications, bOnline is an excellent value proposition first and foremost.

It includes unlimited calling minutes, as its package name suggests, although you now need to pay £5 per month extra for call recording, HD video conferencing and CRM integration respectively.

Depending on what your business requires, that can still work out much cheaper than other business phones on this page, you just won’t have as extensive options as RingCentral or 8×8 for training features or software integrations.

Where could bOnline Unlimited Calling be improved?

While bOnline keeps costs low, it’s only seamlessly compatible with Yealink brand phones. Its most expensive Unlimited Calling plan does come with a handset for each user. However, this essentially locks your business into Yealink rather than a third-party option, which may suit your business needs better.

bOnline also scored less for security measures, although it has improved in recent times. It now has biometric logins, for added layers of authentication, which it previously lacked. It also has relevant data security compliance certifications and password rules for users, though user permissions controls seem to still be missing.

As alluded to above, it doesn’t have as extensive options for training — lacking call barge and whisper tools — or software integrations, not supporting third-party video conferencing, customer service live chat or calendar apps.

Is bOnline Unlimited Calling right for your business?

Overall, bOnline Unlimited Calling is best suited to cost-conscious UK businesses that want core VoIP functionality at a low monthly price, without paying extra for advanced features they won’t use.

✅ Best for businesses that need:

• Budget-friendly calling: A comparatively low per-user monthly price makes this ideal for small teams or startups that want essential VoIP features without a high ongoing cost.
• Straightforward setup: Simple, streamlined services appeal to first-time VoIP adopters or organisations moving from traditional landlines without needing complex configurations.
• Core call management: Essential features, like call routing, ring groups and basic CRM integrations, support customer-facing teams without the need for extensive training or coaching tools.

What Are The Main Types of Business Phone Lines?

There are three types of business phone lines today: the Public Switched Telephone Network (PSTN), the Integrated Services Digital Network (ISDN) and Voice over Internet Protocol (VoIP).

Public Switched Telephone Network (PSTN)

The Public Switched Telephone Network (PSTN) was the original technology for telephone communication invented in the late 1800s. It’s what we call a landline today — the copper telephone lines that run throughout your locale to transmit analogue voice.

Although we’re using modernised PSTN landlines compared with that era, the principle behind its technology has been essentially the same since its conception. And consequently, it’s outdated and expensive to maintain, with the PSTN network set to be switched off by 31 January 2027. Find out why this is important for your business here.

Integrated Services Digital Network (ISDN)

PSTN’s successor, the Integrated Services Digital Network (ISDN) launched in the late 1980s. It digitised the standard landline, enabling the simultaneous transmission of voice and data over copper PSTN wires.

Compared with its predecessor, it offers businesses clearer, higher voice quality, with less distortion and faster data transmission. However, it still relies on the PSTN network for its use, essentially relaying data via more efficient digital transmission. And that means once PSTN switches off in 2027, ISDN will be switched off too.

Voice over Internet Protocol (VoIP)

Finally, we have Voice over Internet Protocol (VoIP), overtaking PSTN and ISDN connections in the business world. As the name suggests, VoIP refers to voice transmission over the internet instead of traditional, physical phone line infrastructure.

This eliminates physical communication barriers, creating a phone system that can grow as your business scales. With everything on a single data network instead of separate phone lines, features like call forwarding are made easier too, while introducing new ones such as video conference calls or voicemail to email data transfer.

It can even be integrated with other business applications such as ecommerce platforms and customer relationship management (CRM) systems. Overall, it outperforms all other business phone lines, particularly in terms of efficiency.

Landline Phone Lines vs VoIP Phone Lines

Now that we’ve defined the different types of phone lines, let’s go a little more in-depth into the difference between landlines and VoIP lines, focusing on three key categories: price, functionality and mobility.

How Do We Compare the Best Business Phone Lines?

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