Porting Your Existing Number to a VoIP Service

Why Porting Deserves a Proper Plan

Moving to VoIP is usually the easy part. Choosing handsets, configuring extensions and setting up a softphone on your laptop can all be done in an afternoon. Porting your existing number across is the bit that catches people out, because it depends on your old provider cooperating, your paperwork being correct first time, and a transfer window that you cannot hurry along.

The good news is that porting is a well-established process in the UK. Ofcom rules mean you have the right to keep your number when you change provider, and your old supplier cannot refuse to release it simply because you are leaving. What they can do is insist that everything is done properly, which is why a little preparation saves an awful lot of frustration.

Know Exactly What You Have Before You Start

Before you fill in a single form, dig out your latest bill and establish precisely what is being ported. The details matter more than most people expect.

• Number type: geographic numbers starting 01 or 02, non-geographic numbers such as 03 and 08 ranges, and mobile numbers all follow different porting routes with different timescales.
• Line configuration: a single analogue line is straightforward. A block of numbers, an ISDN30 range or a number attached to a hosted PBX needs a coordinated port rather than a simple one.
• Broadband dependency: if your broadband shares the same line as the number being ported, moving the number can disturb the broadband. Check whether they are genuinely separate services.
• Account status: the line must be live and the account in good standing. A number that has already ceased is very difficult, and sometimes impossible, to recover.

Write down the account number, the billing address exactly as it appears on the bill, and the full list of numbers you want to move. Slight mismatches here are the single biggest cause of rejected port requests.

The Paperwork That Actually Gets You Moving

Most porting requests fail because of a small administrative error, not because of anything technical. The core document is a Letter of Authority, which gives your new provider permission to act on your behalf and request the number from your old one.

When you complete it, copy the details from your bill character for character. If your business is called "Bramley & Sons Ltd" on the bill, do not write "Bramley and Sons". If the billing address is a unit number, include it. Your new provider will submit the request, and your old provider will compare it against their records. Anything that does not match can bounce straight back.

You may also be asked for:

• A recent bill or invoice as proof of ownership.
• Confirmation of the service address where the number is registered.
• Details of any remaining contract term, so you understand early termination charges before you commit.

Ask your new provider to confirm in writing which numbers they have requested and on what date. Keep that email. It is your reference point if anything drifts.

What Happens During the Transfer Window

Once the request is accepted, you will be given a porting date. For a single analogue line, this is typically around ten working days; multi-line and ISDN ports can take considerably longer, sometimes a month or more.

On the day itself, expect a short outage. Calls to your number may fail for anything from a few minutes to a couple of hours while the routing updates. It is wise to warn regular callers, and to keep a mobile number published on your website and out-of-hours message for that day.

One rule that surprises people: do not cancel your old service before the port completes. If you terminate the line early, the number can be released and lost. Let the port finish, confirm the number is working on the new system, and only then give notice to your old provider.

Mistakes That Cost Time and Money

Most of the pain in porting is avoidable. Watch for these:

• Starting the port too late. If your old contract ends before the port date, you may end up paying for overlapping services or losing the number altogether.
• Assuming it is instant. Plan for at least a fortnight, and longer for complex setups.
• Forgetting the extras. Call divert, fax-to-email, directory listings and any numbers used in printed advertising all need checking once the port is complete.
• Not testing inbound and outbound calls separately. Outbound working does not guarantee inbound routing has caught up.
• Overlooking emergency address details. Update the registered location for the new service so emergency services get accurate information.

Keeping Everything Running Smoothly

Treat a port as a small project with a checklist and a date. Confirm your new VoIP service is fully configured and tested on a temporary number before the port happens, so that the moment your number lands, everything already works. Back up your voicemail greetings, call flows and auto-attendant recordings in advance.

After the port, ring your number from a mobile, ring out to a landline and a mobile, and check that voicemail, transfers and any call recording still behave. Then contact your old provider to confirm the account is closed and ask for final billing in writing.

Done carefully, porting is uneventful. Done in a rush, it can cost you a week of missed calls. Give it the planning it deserves, and your number will follow you into VoIP without anyone noticing it moved.