Business VoIP guide · 2026-05-21

How to Port a Business Phone Number to VoIP: Step-by-Step

A step-by-step walkthrough of porting a UK business phone number to VoIP — what to have ready, how long it takes, and how to avoid the common delays.

Quick answer: To port a business number to VoIP: gather your current bill/account details, sign a Letter of Authority with your new provider, submit the port request, and wait for confirmation — typically one working day for a straightforward single-line port under Ofcom rules.

If you already know what number porting is and just want the practical steps, here's exactly how it works when you move your business number to VoIPninjas.

Step 1 — Gather your account details

You'll need: the phone number itself, the name on the existing account, the billing address/postcode, and ideally a recent bill. These must match your current provider's records exactly, or the port will be rejected.

Step 2 — Sign a Letter of Authority (LOA)

This authorises us to request the port on your behalf. It's a standard, quick form — no need to contact your existing provider yourself.

Step 3 — We submit the port request

We raise the request with your current (losing) provider. For most single-line business numbers this is a same-provider-class port completing within one working day, per Ofcom's General Conditions.

Step 4 — We activate before we cut over

Your new VoIP service is live and tested before the port completes, so calls simply start arriving on the new system — no dead air, no missed calls.

Step 5 — Confirm and test

Once ported, we recommend a quick test call from a mobile to confirm everything's routing correctly, and checking voicemail/auto-attendant settings are as expected.

Common delays and how to avoid them

  • Mismatched details — double-check the billing name and postcode against your current invoice.
  • Multi-line/complex numbers — larger number ranges or PBX trunks can take longer; we'll flag this upfront.
  • Contractual lock-in — porting doesn't cancel your old contract automatically; check your notice period separately.

Want the plain-English version first? Read what number porting actually is.

Related: Compare VoIPninjas plans · VoIP phone systems · Business phone systems UK · PSTN switch-off 2027 · Talk to us

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