Wireless number portability (WNP) enables wireless subscribers to keep their numbers when changing wireless providers. WNP has been mandated in the United States to lower barriers to entry and promote competition in the wireless marketplace by enabling customers to switch to new wireless providers without having to change their telephone numbers. Implementing WNP will enable consumers to select wireless providers based on service, quality, and price, rather than on a desire to keep a particular telephone number. Porting numbers efficiently and cost-effectively between wireless providers requires a sound understanding of operations and interconnection issues and is the focus of this tutorial.