A landline phone is a telephone connected to a line installed at a fixed location such as a home or office. Its structure of area code + local exchange code + subscriber number allows the installation region to be identified from the number itself - its most distinctive feature. The history of landline phones in Japan dates back to 1890, when telephone exchange service began between Tokyo and Yokohama, and they have served as the foundation of communications infrastructure for over 130 years.
Landline subscriptions have been declining steadily with the spread of mobile phones. From a peak of approximately 63 million contracts (subscriber lines plus ISDN) in fiscal 1997, the number fell to about 14 million by the end of fiscal year 2023. Ownership measured per household has also kept falling: the Ministry of Internal Affairs and Communications' Communications Usage Trend Survey (2025 survey, published in May 2026) puts it at 53.6% of households. Younger households are less likely to have one and older households more likely, so a gap by age group remains.
Despite declining subscriptions, landlines still play important roles. In business, having a landline number starting with 03 or 06 enhances corporate credibility. A landline number is sometimes requested when opening an account at a financial institution or during a credit check by a business partner. When making emergency calls (110/119), a landline automatically transmits the registered address tied to the phone number to the receiving center. From a mobile phone, the location sent is a GPS reading when the handset supports GPS and a fix is available, and otherwise a position calculated from the location of the base station. Bundling the line with fiber internet, as Hikari Denwa (fiber-optic phone) does, is another option: NTT East's basic plan costs 550 yen per month including tax as of 2026. It does require a separate fiber-optic subscription such as Flet's Hikari, so the phone service alone is not what the 550 yen buys.
NTT migrated from the PSTN (Public Switched Telephone Network) to an IP-based network through phased regional switchovers from January 2024, completing the transition by January 2025. While the user experience and phone numbers remain essentially unchanged, the underlying technology has shifted from analog circuit-switching to digital packet-switching. This migration ended ISDN data communication (digital communication mode), but voice calls remain available. See How Japanese Phone Numbers Work for the numbering system and How to Look Up Area Codes for identifying regions.