Business Landline Alternatives: What to Replace Your Phone Lines With

Quick answer

There are five realistic business landline alternatives, and for most UK businesses the answer is the first one: a hosted phone system (calls over your internet connection, the "system" in the cloud). A single digital line suits one or two simple phones; SIP trunks suit a good on-site phone system you want to keep; Microsoft Teams calling suits businesses already living in Teams; mobile-only suits sole traders and field-based work. All five keep your existing numbers. The deciding factors are how many people answer calls, whether you have kit you cannot replace, and what your internet connection can carry.

Since Openreach stopped selling analogue lines in September 2023 and the network switches off on 31 January 2027, this is not a question of whether to replace your lines. It is a question of what to replace them with - and it is worth twenty minutes of thought, because the answer sets your phone bill and your call handling for the next five years. This guide compares the options honestly, including the ones we would not sell you. If you would rather see prices for your actual setup, get a no-obligation quote and we will price the alternatives side by side.

Why the "landline" is the thing that changed, not the phone

It helps to separate three things that used to arrive bundled on one copper pair: the connection into your building, the voice service that gives you a dial tone, and the number customers dial. On the old network these were welded together and sold as "a line", which is why losing the line feels like losing everything.

Replacing a landline means buying the first two separately and keeping the third:

• Connectivity - full fibre if you can get it, SoGEA if you cannot yet. Our comparison of SoGEA vs FTTP for business covers which you will end up on.
• A voice service - one of the five alternatives below.
• Your numbers - ported across, unchanged. See keeping your business landline number.

Seen that way the choice gets simpler, because you are only really choosing the middle one.

The five alternatives at a glance

Those price shapes are the honest level of detail an article can give - the actual figure depends on user count, contract length and connectivity. We break the maths down in what the PSTN switch-off costs a business.

Option 1: A hosted phone system

This is the mainstream replacement, and most businesses end up here for good reason. The phone system - the thing that decides where calls go, queues them and reports on them - lives in a provider's data centres rather than a cupboard in your office. Your handsets, laptops and mobiles connect to it over the internet.

What you get that a copper line never offered: direct numbers for staff, an auto-attendant menu, hunt groups and queues, voicemail arriving as email, call recording, and reporting that tells you how many calls you missed last month. The bigger win, consistently underrated, is that calls stop being tied to the building - staff answer the main number from home, a site or a mobile app and callers cannot tell.

The honest trade-off: your phone service now depends on your internet connection and mains power. That needs a deliberate answer rather than a shrug - see landline resilience and failover. A UPS on the router plus automatic divert to mobiles solves it, but only if somebody actually does it.

Option 2: A single digital line

Sometimes called Digital Voice, this is the closest thing to a like-for-like swap: one number, one handset, plugged into your router instead of the wall socket. Dial tone, dial the number, same as ever.

Where it fits: a shop with one phone, a single back-office line, a micro-business where one person answers everything. Where it does not: the moment you want a second person to answer, or calls routed by department, or any reporting, you have bought the wrong thing. Note too that a digital line is a phone replacement - it is not automatically the right answer for an alarm panel or a lift. Our Digital Voice explainer covers how it behaves day to day.

Option 3: SIP trunks into the phone system you already own

If you have an on-site phone system that works, is reasonably recent and does what you need, you do not have to throw it away. SIP trunks deliver call capacity to it over the internet, replacing the ISDN or analogue lines that used to feed it. Your handsets, extensions and call flows carry on unchanged.

This is the option dismissed too early most often, usually by whoever is selling the alternative. It can be the cheapest route by a wide margin because the capital cost is already spent, and the fastest because nobody has to relearn a phone system.

The test is whether the hardware deserves it. A system installed in the last five or six years, still manufacturer-supported, with a maintenance contract and someone who understands it, is worth keeping. One that is out of support, undocumented, or would need a paid upgrade to speak SIP at all, is not - at that point you are paying to prolong a dependency. We work through the decision in can you keep your existing phone system, and compare the two models in SIP trunking vs hosted VoIP.

Option 4: Microsoft Teams calling

If your business already runs on Microsoft 365 and your people live in Teams all day, adding real phone numbers to Teams is a tidy answer. Staff take external calls in the app they already have open, and you have one fewer thing to manage.

It works well for desk-based, office-or-home teams - professional services, agencies, back-office functions. It works less well where the phone is the front door to the business: Teams' call handling, queueing and reporting are serviceable rather than strong. Reception-heavy businesses and anything with a real queue usually want a dedicated system. Our guide to integrating a phone system with Microsoft Teams covers the options, including running a proper phone system behind Teams so you get both.

Option 5: Mobile-only

Dropping the fixed number and running the business on mobiles is a real option, and we would rather say so than pretend otherwise. For a one-person trade business where the phone lives in a van, a business mobile with voicemail is often the whole answer.

Be honest about what you give up: a mobile is one number ringing one handset held by one person, so there is no shared answering, no routing and no cover when that person is up a ladder. A fixed geographic number also still carries weight - an 0161 or 020 number reads as a business with premises in a way a mobile does not. That is why the better version of "mobile-only" is usually a fixed number that simply diverts to a mobile, which costs very little. We cover the trust side in do businesses still need a landline.

Choosing: a decision table

If you have more than one site or more than about a dozen lines, the choice of platform matters less than sequencing the project - that is a different job, and we cover it in migrating multi-site and multi-line businesses.

The part that is the same whichever you choose

Four things apply to all five, and they are where migrations actually go wrong:

1. Your internet connection becomes your phone service. Check what is available at the address and whether it has headroom for calls alongside everything else - see internet speed for VoIP.
2. Power resilience needs a decision. Copper carried its own power; none of these do.
3. The non-phone devices are a separate project. Alarm signalling, lift emergency lines, card terminals, door entry and telecare do not migrate just because your phones did. Read devices that rely on phone lines before you order anything - these have the longest lead times.
4. Port the numbers before you cease the lines. Never the other way round.

Two mistakes worth avoiding

Buying whatever your current provider happens to sell. Providers migrate customers onto their own default product, on a new contract, at their price. That is not a scandal, it is just their job - but it means the product you land on was chosen by them rather than for you.

Sizing on headcount instead of concurrency. You need capacity for calls happening at the same time, which in most offices is far fewer than the number of desks. See multi-line phone systems and channels. And do not leave it late: the phone part is quick, but the alarm, lift and connectivity parts depend on other people's engineers, whose diaries are filling. Our switch-off deadline guide sets out the real lead times.

The bottom line

For most UK businesses the honest answer to "what replaces our landlines?" is a hosted phone system: it costs about what you are paying now, does considerably more, and stops tying your phones to one building. But a single digital line really is enough for a shop with one phone, SIP trunks really are the cheapest route if your existing system is sound, and a fixed number diverting to a mobile really is fine for a sole trader. The wrong answer is the one somebody else picks for you in January 2027.

Tell us what you have and we will tell you which fits, with prices for each: get a no-obligation quote or call 0333 006 9399. We will say so if your existing system is worth keeping.

Getting unknown calls on a business line? Our free UK phone number checker shows which network or provider Ofcom allocated any number to, and whether the range is in service — no sign-up.