WANs, also known as wide area networks, connect LANs over telephone lines and radio waves to form computer networks that cover a large area, even though they might be confined to a single country or state. Enterprises, governmental agencies, and other organizations may connect to WANs. WANs are fast and costly to operate.

WANs are difficult to design and maintain, with switched WAN and point-to-point WAN being the two types. A WAN is less fault-tolerant and has more congestion in the network than a MAN. Telephone lines or satellite links are used for communication. WANs are prone to long-distance noise and errors.

WAN data rates are slower than LAN data rates, because of the increased distance and increased number of servers and terminals involved, plus slower speeds. WAN speeds range from Kbps to Mbps, whereas LAN speeds typically range from Mbps to Gigabits per second (Gbps). The biggest obstacle is the propagation delay. Devices are utilised for WAN transmission in addition to Optic wires, microwave emissions, and satellites. Switched WANs include Asynchronous Transfer Mode (ATM) networks and Point-to-Point WANs, which connect a home computer to the Internet via a telephone line.