How Long Does It Take to Port a Business Phone Number to VoIP?

Porting a single business phone number to a VoIP system typically takes between 7 and 14 working days, from submitting the request to the number going live on your new system. Porting multiple numbers, non-geographic ranges, or numbers with a more complicated history can take two to three weeks. There's no legal maximum for fixed-line business porting the way there is for mobile numbers, so timescales depend largely on your current provider and how accurate your paperwork is.

What Affects How Long Porting Takes?

A few factors consistently make the difference between a smooth week-long port and one that drags on:

• Your current provider — some respond to port requests quickly, others are noticeably slower
• How many numbers you're porting — a single geographic number moves faster than a large range
• Accuracy of your paperwork — mismatched account details or an incorrect Letter of Authorisation are the most common cause of delay
• Number type — standard geographic numbers (01, 02) generally port faster than non-geographic ranges (0800, 0300, 0345)
• Whether the number's been ported before — numbers with a porting history sometimes need extra verification with the original provider

What's the Step-by-Step Timeline?

1. Submit the port request — your new provider raises the request with your current one, using your account details and signed Letter of Authorisation
2. Validation — your current provider checks the details match its records, which usually takes a few working days
3. Scheduling — once validated, a port date is agreed, typically a week or so out
4. Completion — the number goes live on your new system on the scheduled date, usually with minimal or no downtime if managed correctly

Most of the time in this process sits in validation and scheduling, not the technical transfer itself, which normally happens within a matter of hours on the agreed date.

Is VoIP Porting the Same Speed as Mobile Porting?

No, and this is a common source of confusion. Mobile number porting in the UK is fast — often same-day — because Ofcom's switching rules specifically require mobile providers to issue a code within minutes and complete the transfer quickly. Fixed-line and business VoIP number porting doesn't fall under those same fast-switching rules, so the realistic timescale is measured in working days rather than hours, regardless of which VoIP provider you're moving to.

What Can Delay a Port?

Mismatched account details If the name, address, or account number on your port request doesn't exactly match your current provider's records, the port will likely be rejected and need resubmitting.

Cancelling your existing line too early Ending your current contract before the port completes can cause the number to be disconnected before the transfer finishes, sometimes losing it altogether. Keep your existing service active until the port is confirmed complete.

Outstanding balances Some providers won't release a number if there's an unpaid balance on the losing account, so it's worth checking your account is up to date before starting.

An unresponsive current provider Occasionally, a losing provider simply takes longer than expected to process a request. There's not much you can do about this beyond your new provider chasing on your behalf, which is one reason it's worth using a provider experienced at managing ports.

How to Avoid Delays

• Double-check every detail on your port request against a recent bill from your current provider
• Get your Letter of Authorisation signed by someone with genuine authority on the account
• Don't give notice to cancel your existing service until the port is confirmed
• Build a realistic buffer into any migration plan — don't schedule a hard cutover date until the port is confirmed, particularly if you're working against a deadline like the PSTN switch-off

Frequently Asked Questions

Can I port a number if I'm switching to a different type of system, like from ISDN to VoIP? Yes. Porting works the same way regardless of what technology you're moving to or from — it's the number that transfers, not the underlying line type.

Will there be any downtime while my number ports? There shouldn't be, if your existing service stays active until the port completes and the transfer is scheduled properly. Any downtime is usually a sign something in the process wasn't managed correctly.

Can I speed up a business number port? Not really, beyond making sure your paperwork is accurate the first time, since most delays come from resubmissions rather than the process itself being slow.

Do all business numbers qualify for porting? The vast majority of UK geographic and non-geographic business numbers can be ported. A small number of legacy or specialist ranges may have restrictions, which your new provider can confirm.

Getting porting right the first time is mostly about accurate paperwork and realistic timing, not luck. Request a quote if you'd like T2K to manage your port as part of a move to Gamma Horizon or 3CX, or use our PSTN switch-off checker to see how much time you've got to plan the move.