Can I keep my number when switching to VoIP? (number porting)
Yes. You can keep your existing business number when you move to VoIP through a process called number porting. Your new provider transfers the number across from your old one, so customers keep dialling the same number with no change. A single geographic number usually ports in a few working days, and porting is free with most providers.
How does number porting work?
Porting is the official process for moving a phone number from one provider to another while keeping the number itself. When you switch to VoIP, your number is not tied to a physical copper line any more. It becomes a record on your new provider's system that tells the network where to route incoming calls. Your new VoIP provider manages the whole transfer for you.
The steps are simple from your side. You sign up with the new provider, give them the numbers you want to keep and a recent bill or proof of ownership, and they raise a porting request with your current provider. The two providers agree a date, the number switches over on that date, and your old line is closed afterwards. You do not have to deal with your old provider directly.
The one rule that matters most: do not cancel your old line before the port completes. A ceased number cannot be ported and can be lost for good. Keep the old account live until your new provider confirms the number has moved. For the full process of moving across, see our step-by-step guide to switching your business to VoIP.
How long does number porting take in the UK?
Porting time depends on the type of number and how many you are moving. A single geographic number is quick, while large ranges and non-geographic numbers take longer because more parties and checks are involved. Your provider gives you a confirmed porting date once the losing provider accepts the request, so you always know when the switch happens.
| Number type | Typical porting time | Notes |
|---|---|---|
| Single geographic (01 or 02) | A few working days to ~10 working days | The most common and quickest port |
| Multiple or large geographic ranges | ~10 to 25 working days | More numbers means more checks |
| Non-geographic (03, 0800, 084x) | ~15 to 25 working days | Routed through central databases |
| Numbers with errors on the account | Can be longer | Mismatched address or name delays it |
The biggest cause of delay is a mismatch between the details your new provider submits and the details your old provider has on file. A wrong postcode, a slightly different business name or an out-of-date address can bounce the request. Sending a recent bill and double-checking the account details up front avoids almost all of these hold-ups.
Can I keep an 0800 or 0333 number?
Yes. Non-geographic numbers move to VoIP in the same way as standard landline numbers, and they often work better on a hosted system than on the old network. An 0800 freephone number, an 0333 or 0345 national number, and 084x numbers can all be ported. They simply take a little longer than a local number because they are managed through central industry databases.
VoIP also makes these numbers more flexible once they have moved. You can point an 0800 number at a different team, an auto-attendant menu, or different sites depending on the time of day, and change the routing yourself in minutes. On a traditional line, that kind of change meant a request to your provider and a wait.
How do I switch without losing any calls?
The key to a clean switch is preparation. Your VoIP system should be fully built and tested before the porting date, so the moment your number moves, the calls land on a working setup. A good provider configures your users, call routing and voicemail in advance, and may run the new system in parallel on a temporary number so you can test real calls first.
On the porting day itself, the number usually switches within a short window. Calls that were ringing on the old line stop, and new calls arrive on VoIP. Because everything is ready, the gap is minimal and most businesses notice nothing. If you want belt-and-braces cover, your provider can set inbound calls to also ring a mobile during the cut-over, so a call can never go unanswered.
One more reason to plan the move now rather than later: the old analogue network is being retired. The PSTN and ISDN switch-off on 31 January 2027 means every business will need to move its lines to an internet-based service. Porting your number to VoIP is exactly how you keep it through that change.
Frequently asked questions
Can I keep my existing phone number when I move to VoIP?
Yes. Almost any UK business number can be moved to a VoIP provider through a process called number porting. This includes geographic 01 and 02 numbers, 03 numbers such as 0333 and 0345, and 0800 freephone numbers. Your new provider handles the transfer with your old provider, and you keep the same number.
How long does it take to port a number in the UK?
A single geographic number usually takes a few working days to around ten working days. Larger ranges and non-geographic numbers such as 0800 can take longer, often two to four weeks, because more parties are involved. Your provider gives you a firm porting date once the request is accepted.
Will my phone stop working while the number is being ported?
No, if it is planned properly. Your old line keeps working right up to the agreed cut-over, and the switch to VoIP happens on the porting date itself, usually within a short window. A good provider sets up your VoIP system in advance so you are ready to take calls the moment the number moves.
Should I cancel my old phone line before porting?
No. Never cancel the old line first. If the number has already been ceased, it cannot be ported and may be lost. Let the porting complete, then your old provider closes the line automatically. Keep the account open until the new provider confirms the port is done.
Does porting a number cost anything?
Most VoIP providers port standard numbers for free as part of switching. Some charge a small one-off fee for large ranges or complex non-geographic numbers. Always confirm porting costs in writing before you sign up so there are no surprises.
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