Switching from Landline to VoIP: The Complete Guide for UK Businesses

Six months. That’s roughly how long UK businesses have until the traditional analogue phone network is switched off for good in January 2027. If your business is still running on landlines, the question is no longer whether to switch to VoIP, but how to do it without disruption, and how to avoid the traps along the way.

This guide walks you through everything: what VoIP actually is, how it compares to your landline, whether you can keep your number (yes, you can), what the switch involves step by step, and what it’s likely to cost.

VoIP vs landline: what’s actually different?

VoIP stands for Voice over Internet Protocol. Instead of sending calls down a dedicated copper phone line, VoIP sends them over your broadband connection as data. That single change is behind almost every practical difference:

• Cost. No line rental for a separate phone line, cheaper call rates, and free calls between colleagues wherever they are. Most businesses see their phone bills fall noticeably after switching.
• Flexibility. A landline lives in a wall socket. A VoIP number lives in the cloud, so you can answer your business line on a desk phone in the office, an app on your mobile, or a laptop at home, all with the same number.
• Features. Things that used to require an expensive on-site phone system come as standard with hosted VoIP: call routing, auto attendants, voicemail to email, call recording, hunt groups and hold music.
• Scalability. Adding a new starter to a traditional system might mean an engineer visit. With VoIP, it’s a few clicks and a handset in the post.
• Future-proofing. The copper network that landlines depend on is being retired in January 2027. VoIP is what replaces it, so a switch now is a move you’d have to make anyway, done on your own timetable rather than a deadline.

The honest downside: VoIP depends on your broadband and your power supply. If your internet goes down, so does your desk phone. In practice this is managed easily with automatic failover to mobiles, and a decent business broadband connection handles call traffic without breaking a sweat. But it’s the one dependency worth planning for, and a good provider will design that resilience in from day one.

Can I keep my landline phone number with VoIP?

Yes. This is the single most common worry we hear, and it’s the easiest to put to bed. The process is called number porting, and it means your existing business number moves with you to your new VoIP service. Your customers dial the same number they always have; the call simply arrives over the internet instead of the copper line.

Porting typically takes between one and three weeks depending on your current provider, and your old line keeps working right up until the moment the number transfers, so there’s no gap in service. The only real rule to remember: never cancel your old line before the port completes. Cancelling first can mean losing the number entirely.

Is VoIP reliable enough for business?

Modern business VoIP is extremely reliable, and in some respects more resilient than the ageing copper network it replaces. Call quality on a properly configured connection is at least as good as a landline, and often better, with HD voice as standard.

Reliability comes down to three things: a solid broadband connection, correct setup (particularly prioritising voice traffic on your network), and a provider with a track record. This is where a specialist matters more than a household name. A provider that configures your system properly and answers the phone when you need help is worth far more than a marginally cheaper self-service platform.

How to switch from landline to VoIP: step by step

1. Audit what you have. List your current lines, numbers, handsets and any equipment that plugs into a phone socket. Don’t forget the non-obvious items: alarms, door entry systems, card machines and fax lines all need a migration plan of their own. Our guide to the landline switch-off covers these in more detail.

2. Check your broadband. Each concurrent call uses roughly 100Kbps, so even a modest fibre connection handles a small office comfortably. If your broadband is older or already straining, upgrade it as part of the project rather than after problems appear.

3. Choose your setup. Most businesses opt for hosted VoIP, where the phone system lives in the cloud and you simply plug in handsets or install apps. There’s no equipment room, no maintenance contract, and updates happen automatically.

4. Port your numbers. Your new provider handles this for you. You’ll sign a letter of authority, and the numbers transfer on an agreed date.

5. Set up call routing before go-live. Decide how calls should flow: who rings first, what happens when nobody answers, opening hours, voicemail greetings. Getting this right before the switch means day one feels seamless to your customers.

6. Go live, then cancel the old line. Once your numbers have ported and you’ve made test calls in both directions, the old line can be cancelled. In that order, always.

What does business VoIP cost?

Hosted VoIP is priced per user per month, typically somewhere between £5 and £15 depending on the features and call bundles included, with handsets either purchased outright or included in the monthly fee. Compare that with line rental alone on a traditional multi-line setup and the savings are usually immediate, before you count cheaper calls and the maintenance contracts you no longer need.

Be wary of headline prices that look too good. The cheapest deals often exclude UK support, charge extra for essentials like call recording, or lock you into long contracts with steep exit fees. Ask for the all-in monthly figure for your actual usage before signing anything.

Frequently asked questions

What is a VoIP phone system?

A VoIP phone system is a business telephone system that carries calls over your internet connection rather than traditional phone lines. With hosted VoIP, the system itself runs in the cloud, so there’s no physical phone system on your premises to buy or maintain.

Do I need new phones?

Not necessarily. Many businesses use a mix of dedicated VoIP desk phones, mobile apps and computer softphones. Some existing handsets can be adapted, though modern VoIP handsets are inexpensive and generally worth the upgrade.

Will VoIP work with my broadband?

Almost certainly. Voice calls use very little bandwidth. Unless your connection is very old or very congested, standard business fibre is more than enough.

What happens to VoIP in a power cut?

Desk phones need power, but your number doesn’t stop working. Calls can automatically divert to mobiles, so your business stays reachable even if the office goes dark.

How long does switching take?

A straightforward small business switch typically completes within two to three weeks, driven mostly by number porting timescales. The disruption to your team is usually measured in minutes, not days.

Make the switch on your terms

Every business in the UK will be on VoIP within a couple of years, because the network that landlines run on is going away. The only choice is whether you switch calmly, on your own schedule, or in a rush as the deadline closes in.

Planet Telecom has been helping UK businesses with their communications for over 27 years, and we handle the whole move for you: number porting, setup, call routing and ongoing UK-based support. Take a look at our business VoIP service, or call us on 0345 077 7777 for a straightforward conversation about what the switch would look like for your business.