Switch-off 2027

How to port your UK phone number to VoIP: STAC and PAC, step by step

PSTN switch-off2026-05-036 min readBy Silux Call team

PAC, STAC, and the timelines that actually apply. The exact steps to move a UK landline or mobile number to a VoIP provider without losing a single call.

Landline (STAC)

  1. Request your STAC code from your current provider. Free, must be issued within one working day under Ofcom rules.
  2. Give the STAC + your billing address to Silux Call.
  3. We submit the port. Cut-over typically completes within 24 hours.
  4. Test before you cancel anything.

Mobile (PAC)

Text PAC to 65075 from the SIM you want to port. You receive a PAC code within a minute. Give the PAC to Silux Call within 30 days.

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 number-by-number.

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