What Is Number Portability?

Mobile Number Portability (MNP) is a feature that allows you to keep your existing phone number when you switch from one telecommunications provider to another. Introduced in most countries to promote competition, it means your number is truly yours — not tied permanently to any one carrier.

Number portability applies to:

  • Mobile-to-mobile transfers (switching between mobile carriers)
  • Landline-to-landline transfers
  • In some regions, mobile-to-landline or VoIP transfers

Why Number Portability Is Important

Before MNP existed, changing your phone provider meant getting a completely new number — a significant inconvenience. You'd have to notify every contact, update business cards, change account logins, and risk missed calls during the transition. Number portability eliminates this barrier, giving consumers more freedom to:

  • Switch to carriers offering better pricing or coverage.
  • Move between prepaid and postpaid plans.
  • Transition from a landline to a mobile or VoIP service.

How Does the Porting Process Work?

The process differs slightly by country, but generally follows these steps:

  1. Choose your new provider and sign up for a plan.
  2. Request a port — your new provider initiates the transfer on your behalf.
  3. Provide your account details from your current provider, including your account number and PIN/password.
  4. Wait for the transfer — in most countries this takes between a few hours and 3 business days.
  5. Your old SIM stops working and your new SIM activates with your existing number.

Important: Do not cancel your old account before the port is complete. Cancelling early can cause you to lose your number entirely.

What Is an Account Transfer PIN?

In the US, carriers are required to provide you with a Number Transfer PIN (also called a porting PIN or PAC code in the UK). This is a security code used to authorize the transfer of your number. You can usually obtain it by:

  • Logging into your current carrier's app or website.
  • Calling your carrier's customer service.
  • Sending a text message (in the UK, text "PAC" to 65075).

Can You Port Any Number?

Most numbers are portable, but there are some exceptions:

  • Toll-free numbers (800, 888, etc.) have their own portability process managed separately.
  • Numbers under a business account may require additional authorization.
  • Numbers from inactive accounts may not be portable if the original account has been closed.
  • Geographic landline numbers in some countries cannot be ported to a mobile carrier.

Does Porting Affect Your Number Format?

No — when you port your number, the digits remain exactly the same. However, in the background, the routing data in carrier databases is updated to point your number to the new network. This is why caller ID databases and reverse lookup services sometimes have a delay — they need time to update their records after a port.

Tips for a Smooth Number Port

  • Don't cancel your old account until the port is fully complete.
  • Make sure your account is in good standing — unpaid bills can delay or block porting.
  • Double-check your account details — incorrect information is the most common reason ports fail.
  • Expect a brief service interruption of up to 30 minutes during the actual switchover.
  • Keep your old SIM handy until you've confirmed the new one is working.