Area Code 2640 – Nagano, Nagano

Overview of Area Code 2640

Area code 2640 is a geographic National Destination Code (NDC) within the Japanese telephone numbering plan, assigned to the city of Nagano, the capital of Nagano Prefecture, located in the Chūbu region of Honshū, Japan. This code is part of the larger 026 area code cluster, which serves central Nagano Prefecture. Specifically, 2640 is allocated to the Nagano urban area, including the central wards of Nagano City and its immediate suburbs. The code is administered by the Ministry of Internal Affairs and Communications (MIC) and operated by NTT East, the regional incumbent carrier.

Dialing Formats and Usage

When dialing a number within the 2640 area code from another part of Japan, the trunk prefix '0' is used: 02640-XXXXXX. The subscriber number is six digits long, making the total national significant number (NSN) length 10 digits (including the leading zero). For international callers, the country code for Japan is +81, and the leading zero is dropped, resulting in the format: +81 2640-XXXXXX. For example, a local number such as 02640-123456 would be dialed as +81 2640-123456 from abroad.

Within the same exchange area, callers may often omit the area code and dial just the six-digit subscriber number, but this practice is becoming less common with the proliferation of VoIP and mobile services. It is always safe to include the full national number.

Geographic Coverage and Administrative Jurisdiction

The 2640 area code serves the Nagano City area, which is the prefectural capital and a major economic and cultural hub. Nagano City is famous for the 1998 Winter Olympics and is surrounded by the Japanese Alps. The code covers the city's central districts, including the Nagano Station area, Zenkoji Temple vicinity, and residential neighborhoods. It does not cover the entire prefecture; other parts of Nagano Prefecture use different area codes such as 0261 (Matsumoto), 0265 (Iida), and 0266 (Suwa).

Overlay and Numbering Considerations

Currently, there is no overlay code for the 2640 area. The numbering capacity is sufficient for the population density. However, as with all Japanese geographic codes, number portability allows users to retain their numbers when switching between fixed-line carriers, but the geographic tie remains. VoIP services may also use this code, but they are required to provide location information for emergency calls.

Caller Instructions

• Local callers (within Nagano City): Dial the six-digit subscriber number directly if the call is within the same charging group; otherwise, dial 02640-XXXXXX.
• National callers (from other parts of Japan): Dial 02640-XXXXXX.
• International callers: Dial your country's exit code (e.g., 011 from the US), then Japan's country code 81, then 2640, then the six-digit subscriber number: +81 2640-XXXXXX.

For accurate billing and routing, always verify the complete number with the recipient. The 2640 code is a standard geographic code, and calls to it are typically charged at domestic rates when dialed from within Japan.