An active number is already connected to a mobile service. A New Unregistered SIM is supplied as not yet activated or registered by its seller. These are different starting points: check activation status and transfer method separately before buying or listing.
Separate the number, SIM and service
The mobile number is the contact identifier. The SIM or eSIM is the means of connecting a device to a provider’s service. The tariff sets the ongoing allowances and charges. Buying a memorable number does not automatically include a new handset, a tariff or unlimited credit.
A seller’s description of a new SIM is a statement about that item’s status. It is not, by itself, independent proof that the telephone number has never appeared on an earlier service. Avoid using “never used” as a promise unless there is evidence that supports it.
Compare the two starting points
| Question | Active number | New Unregistered SIM |
|---|---|---|
| Can it receive a verification SMS now? | An accessible active line may be able to complete the SMS check. | It may not be active to receive a message. PYN uses a separate review route. |
| How might I receive it? | The listing may use PAC transfer, subject to the provider’s process. | PYN’s physical-SIM route is for New Unregistered stock. |
| What should I check? | Current network, transfer arrangements and access to the line. | Network, packaging/evidence, delivery arrangements, expiry and activation requirements. |
Activation requirements are provider-specific
Follow the instructions supplied for the actual SIM rather than a generic rule from another network. For example, O2’s SIM guidance says its Pay As You Go plastic SIM is activated by inserting it into a device and topping up. That example should not be assumed to apply to every provider or product.
If a listing includes an expiry date, check it before buying and plan to activate in time. If the date is unknown, ask for clarification. Keep the packaging and instructions until you have confirmed that the number and service work as expected.
Also confirm that your device supports the supplied SIM format or the receiving provider’s eSIM process. A physical SIM purchase does not automatically provide an eSIM conversion.
PAC transfer is a separate process
A PAC is used to keep a number when switching providers. Ofcom’s guidance says the receiving provider must complete the switch within one working day once the switching process is initiated. Check arrangements and timing with that provider; do not treat this as a guaranteed delivery date for a marketplace purchase. See Ofcom’s guidance.
Moving between tariffs on the same network may need that network’s own procedure. O2, for example, publishes separate instructions for moving between its Pay As You Go and Pay Monthly services. Ask before assuming you need a PAC for a same-network change.
What should a PYN seller enter?
Choose the status that describes the SIM now, not the status you hope it will have later. State the current network, choose a suitable transfer method and provide any known expiry. On PYN, physical SIM shipping is for New Unregistered SIMs. Follow the verification or evidence steps shown for the chosen route.
If you activate the SIM after submitting it, the saved details may no longer describe the item accurately. Update the listing or contact PYN before a buyer relies on those details. Do not put a PAC, account password or verification code in a public description or uploaded photograph.
Choose the route that fits your plan
An active line can suit someone planning a supported transfer; New Unregistered stock can suit someone happy to receive and activate a physical SIM. Neither label alone proves that a number is better, more valuable or safer. Compare the actual listing and the steps involved. Read the PAC guide if you plan to move between networks.
Sources and further reading
- O2: SIM activation and replacement
- Ofcom: switching mobile phone provider
- O2: switching between its tariffs
External sources checked on 3 November 2026. PYN route descriptions explain the marketplace workflow; network examples are not promises about every SIM or order.