What is mobile number portability?
Mobile number portability is an international telecommunications rule that requires wireless service providers to allow customers with eligible phone numbers to retain their phone numbers when changing service providers. Within the European Union,mobile number portability is now regulated and enforced in almost all member states. This law imposed by the Telecommunications Regulators of the European Union allows all citizens of E.U. Countries to enjoy the benefits of competition.

Which Numbers are eligible to port?
All mobile numbers regardless of post paid or prepaid service are allowed to port between providers. The only exception is post paid numbers which are under contract for a certain period of time. In this case you have to wait until the contract is expired