A leased line is a bidirectional telephone line that has been rented for private voice, data exchange or telecommunication use. Typically, organizations purchase leased lines from telephone message carriers to interconnect different geographic locations. In some contexts, a leased line may be referred to as a dedicated line.

A leased line is a reserved circuit between two communication points that is always active and rented monthly. Leased lines are dedicated, meaning that any bandwidth associated with the leased line is solely for private, organizational use. This is different from traditional telecommunications methods that reuse the same circuit through switching.

Leased lines create a constant tunnel between two points to enable a continuous data flow. Typically, the first location is a corporate office with the second location set as another corporate office, a data center or a corporate wide area network. The line itself runs on high-speed, high-capacity fiber optic cables.