What is MNP (mobile number portability)?
MNP — mobile number portability — lets a subscriber keep their phone number when switching carriers, which is why the number’s prefix no longer tells you who actually serves it.
Definition
Mobile Number Portability (MNP) is the regulatory mechanism that lets a subscriber move to a different mobile operator while keeping their existing phone number. It exists in most markets worldwide — mandated in the EU since 2003 and in the US since 2004 — and porting volumes are large enough that in mature markets well over 10% of numbers no longer belong to the operator that originally issued them.
Technically, MNP breaks the historical assumption that a number’s prefix identifies its network. Once a number is ported, routing databases — either a central national MNP database or the donor network’s records — must be consulted to find the current serving operator. An MNP lookup queries exactly that: it returns the live MCC/MNC of the network that serves the number today. Messaging platforms depend on this because SMS termination fees differ per network, and sending via the wrong route based on the prefix alone means paying the wrong rate or failing delivery entirely.
Why it matters
If you route or price SMS by number prefix you are guessing, and in a market with heavy porting you are guessing wrong a double-digit percentage of the time. MNP data is what turns routing from folklore into fact — correct termination fees, correct carrier, correct country of the actual subscriber.
See it in action
Check a number’s live carrier with HLR lookup →