Nippon Telegraph and Telephone Corporation provides fixed voice-related, mobile voice-related, IP/packet communications, and system integration services in Japan and internationally.

The company's Integrated ICT Business segment offers mobile communications services and smart life area services; provision of inter-prefectural communications services, international communications services, and internet-related services; and provision of internet connection and video distribution services, as well as engages in the development, production, operation, and maintenance of information communications systems and software.

Its Regional Communications Business segment provides intra-prefectural communications services and related ancillary services.

The company's Global Solutions Business segment offers IT services and communications, and internet-related services.

This segment primarily provides cloud, data center, and maintenance support, IT system building, data communications system, professional security, ICT, network, managed, mobile connectivity, consulting, system design and development, and other services, as well as teleconference, web conference, and video conference services.

Its Other Business segment engages in the acquisition, development, construction, lease, and management of real estate; design, management, and maintenance of buildings, equipment, and electric power facilities; development of smart energy solutions and energy management systems; credit card transaction settlement activities; billing and collection of charges for communications and other activities; design and development of systems; and technology transfer and technical consulting businesses.

It also sells telecommunications equipment.

The company was founded in 1952 and is headquartered in Tokyo, Japan.