The Japanese networks of telecommunications and of postal services are among the best and most sophisticated in the world. The hundreds of islands, as well as the remotest villages deep in the mountains, are effectively linked by these services. Japan is now a world leader in the use of advanced telecommunications, including satellite and fiber optic transmission networks. Per capita telephone ownership is high; although the number of landlines has steadily declined since the late 1990s, mobile-phone subscriptions have soared. The use of personal computers and connections to the Internet have become nearly universal throughout the country.

The government began privatizing the telecommunications industry in the mid-1980s, starting with Nippon Telegraph and Telephone (NTT), provider of domestic telecommunications services. NTT became one of the largest private firms in the world, but in 1999 it was broken up into a number of subsidiary companies under the name NTT Group. Also at that time the monopoly on international telecommunications services that long had been held by the semipublic Kokusai Denshin Denwa (KDD) was lifted; KDD subsequently was wholly privatized, and, after a series of mergers, was renamed KDDI Corporation. A number of other private telecommunications companies also operate in the country.