Area Code 2387 – Nagai, Yamagata

Overview of Area Code 2387

Area code 2387 is a geographic National Destination Code (NDC) assigned to the city of Nagai and its surrounding areas in the Yamagata Prefecture of Japan. This code is part of the Japanese numbering plan under ITU-T E.164, where the country calling code is +81. The region is served by the Nippon Telegraph and Telephone (NTT) network, and the code is used for fixed-line (PSTN) services.

Geographic Coverage and Administrative Jurisdiction

The 2387 area code covers Nagai City and adjacent municipalities, including parts of the Nishimurayama District. Nagai is a regional hub in the southern Yamagata Prefecture, known for its agricultural production and scenic landscapes. The administrative jurisdiction falls under the Yamagata Prefectural government, and the area is serviced by NTT East (NTT Higashi-Nihon).

Dialing Formats and Instructions

For callers within Japan, the local dialing format is 02387-XX-XXXX, where 02387 is the full prefix (including the trunk prefix 0 and the area code 2387). The subscriber number typically consists of 6 digits, making the total national significant number (NSN) 10 digits when including the area code.

For international callers, the format is +81 2387-XX-XXXX. Note that the leading 0 of the area code is dropped when dialing from abroad. For example, to call a number in Nagai, you would dial +81 2387 123 456 (using a placeholder subscriber number).

Overlay Considerations and Numbering

Currently, there is no overlay code for the 2387 area. The area code is unique to the Nagai region, and no additional area codes have been introduced. This means that local calls within the same area code can be made using the 6-digit subscriber number alone (without the area code) in many cases, but for clarity and to avoid misdialing, it is recommended to use the full 10-digit format when calling from mobile phones or other regions.

Caller Instructions

• Local callers (within 2387): Dial the 6-digit subscriber number directly (e.g., 123 456).
• National callers (outside 2387): Dial 0 followed by 2387 and the subscriber number (e.g., 02387 123 456).
• International callers: Dial your country's exit code, then 81, then 2387, and the subscriber number (e.g., +81 2387 123 456).

When calling from a mobile phone in Japan, it is common to include the area code even for local calls to ensure proper routing. The Japanese numbering plan is strictly regulated by the Ministry of Internal Affairs and Communications (MIC), and area codes are assigned based on geographic boundaries.