What is number porting and why can it matter to an investigation?¶

A telephone number may stay the same even though the provider changes.

Evidential caution: that the current provider held the number throughout the whole period under investigation.

What this means¶

Number porting allows a customer to move a telephone number from one provider to another. The number remains familiar, but the network responsible for it changes.

This matters because records may be split across providers. One provider may hold subscriber and usage information for the earlier period, while another holds later records.

A port can also affect preservation and request timing. Sending an enquiry only to the current provider may miss relevant historical data.

Provider terminology can be confusing. Distinguish the original donor network, the receiving network and any intermediary routing information.

Consider whether the port was legitimate. In fraud cases, an unauthorised port-out may explain loss of service, account takeover or control of authentication messages.

In reports, explain which provider held the service at each stage rather than treating the number as tied permanently to one network.

What to check or do next¶

• Preserve the full number, date range and any known provider information. Establish whether and when the number was ported.
• Seek subscriber, account, SIM and porting records for the relevant periods where lawful and proportionate.
• Record the effective date and time of the port. Communications immediately before and after the transfer may sit in different systems or be explained by service interruption.

Evidential limits¶

Porting does not prove who used the number. It shows movement of the service between providers.