How to port your UK phone number to VoIP (PAC and STAC explained)

UK number portability is a regulator-mandated right. You can keep your existing landline number when you change provider, free of charge.

What you need

1. The numbers you want to bring, exactly as your current provider bills them. A consecutive block can be given as a range.
2. The installation address — where the line physically is. Your current provider matches this field by field, so copy it from a bill rather than typing it from memory.
3. A recent bill (last three months) showing the numbers and that address.
4. A signed letter of authority. Silux Call generates one from your request for the account holder to sign, or you can upload your own.
5. The address to register for 999 / 112 calls, so the emergency services are sent to the right place.

How long it takes

A landline port depends on your current provider releasing the number. Your existing line keeps working until the switch completes, so you never lose a call. Porting out is always free and we release a number within 24 hours of a valid request, in line with Ofcom rules.

Common gotchas

• Outstanding contract — your old provider must clear early-termination fees first.
• Address mismatch — keep the old bill address until the port completes.
• Multi-DDI ranges — port the whole range with one submission, not one at a time.