Telephone number portability can refer to:

In the United States, telephone number portability as mandated by the FCC takes effect in major metropolitan areas.

The U.S. FCC since has mandated Wireless Local Number Portability starting November 24, 2003 (in metropolitan areas), and allowed operators to charge an additional monthly Long-Term Telephone Number Portability End-Use Charge as compensation.

Federal surcharges and pass-along charges include money for telephone number pooling, which is designed to reduce the proliferation of telephone numbers and area codes; telephone number portability, which allows customers to retain their phone numbers if they switch carriers, and the universal service fund, which helps rural schools and libraries enter the digital age.