Glossary

What is mobile number portability?

Mobile number portability, often shortened to MNP, is the ability for a subscriber to keep their existing phone number when they switch to a different carrier. It means a phone number's current carrier is not a fixed fact about that number: it can change independently of who holds the number or how long they have held it, which matters whenever a fraud or KYC process relies on a carrier lookup.

Why portability exists

Before portability, switching carriers meant losing your number, which locked subscribers into their existing provider. Regulators across the UK, EU and most other developed telecoms markets have required number portability for years specifically to keep the market competitive: a subscriber can move to a cheaper or better carrier without having to tell everyone they know a new number.

What this means for a carrier lookup

A carrier lookup tells you which network currently serves a number, not which network originally issued it. A number that shows as belonging to a particular carrier today may have been issued by a different carrier years earlier, and the subscriber may have ported it more than once since. Treat the result as "who serves this number right now", not as a record of the number's history.

What this means for fraud screening

A recently ported number is not, by itself, a sign of fraud. Porting is a routine consumer action that happens continuously across every market as people switch providers for price, coverage or contract reasons. It is one input among several, not a standalone red flag, and it is best combined with number type, active status and other signals rather than treated as a rule on its own.