How to Switch from PAYG to Contract on the Same Network

Confirm that the provider treats it as an internal move

Tell the provider that the existing PAYG number must remain on the new monthly service. Do not request a PAC unless the provider explicitly says that the old and new services are handled as separate providers or brands. A mistaken external port can create unnecessary delays.

Check before agreeing

• Exact monthly price and minimum term
• Any pounds-and-pence annual rise written into a new contract
• Data, roaming, tethering and Wi‑Fi Calling terms
• Whether the same physical SIM can be reused or a new SIM/eSIM is required
• What happens to PAYG credit, bundles and rewards
• Whether a credit check is required
• Whether the phone is unlocked and compatible with the new service

Prepare account access

Make sure the PAYG account name, date of birth and address are correct. Save important 2FA recovery codes and keep the old SIM until calls, SMS and data work on the monthly account. If the provider issues a temporary number, obtain written confirmation that the PAYG number will replace it.

Verify the migration

1. Call another phone and check the displayed number.
2. Call the number from a different network.
3. Send and receive SMS.
4. Test mobile data with Wi‑Fi off.
5. Check voicemail and the online account.
6. Confirm that PAYG auto top-up is disabled only after the move is complete.

When an internal migration is not available

Some providers or sub-brands may require a different route. Ask for the exact written process before ordering. If a PAC is required, follow the normal number-porting sequence and do not cancel the PAYG service first.

A safe completion check

An internal migration should preserve the number without a normal inter-provider port, but the process can still issue a temporary SIM or require a replacement profile. Confirm the provider's exact route before ordering and keep the PAYG line active until the monthly service works in both directions.

• Ask whether unused credit is retained or lost.
• Do not update accounts to a temporary number.
• Test data, calls, SMS and voicemail after migration.

If the monthly plan starts with a temporary number

Record the temporary number, but do not update banking, messaging or recovery services to it. Ask the provider to confirm in writing when the existing PAYG number should replace it.

If outgoing calls show one number while incoming calls or texts still reach the other SIM, treat this as an incomplete migration. Keep both SIMs available and report the exact direction, time and affected service to the provider.