Can You Keep Your Business Telephone Number When Switching Provider?

Almost every UK business telephone number can be ported from one provider to another. The process is regulated by Ofcom, standardised across UK carriers, and used every single working day.

How porting works in practice

Your new provider raises a port request with your current provider on your behalf. The two carriers agree a date. On that date, at an agreed time, the number moves. If everything is prepared correctly, downtime is usually measured in seconds — not minutes, and certainly not hours.

For VoIP-to-VoIP ports, this is fast and low-risk. For analogue lines still using PSTN or ISDN, there are more moving parts, and a good provider will build extra time in for testing.

What can go wrong

• Account name on file with the current provider does not match — the single most common cause of delays.
• Number is still under a service contract with financial commitments outstanding.
• Port date falls on a day when key staff are unavailable to test.
• Current provider rejects the port for an administrative reason (address mismatch, missing authority to port).
• A separate equipment-finance agreement continues after the service moves.

What to check before you commit to a new provider

• Get your latest bill in front of you — the exact account name and billing address must match.
• Confirm your notice period and any early-termination charges before porting.
• Ask the new provider for the port lead time in writing (typically 10–15 working days for standard numbers).
• Agree an out-of-hours cutover if calls are business-critical.
• Test with a two-way call from a mobile as soon as the number moves.

Numbers that are harder to port

Some non-geographic ranges, freephone numbers on legacy carriers, and numbers tied to specific network-level features can take longer or require a more careful migration. In practice, we have not encountered a UK business number that cannot ultimately be moved — it just occasionally takes a bit more planning.