Area Code 2573 – Kashiwazaki, Niigata

Geographic Context and Coverage

The area code 2573 is a geographic National Destination Code (NDC) assigned to the city of Kashiwazaki and its surrounding areas in Niigata Prefecture, Japan. This code is part of the Japanese numbering plan, which follows ITU-T E.164 recommendations. Kashiwazaki is a coastal city on the Sea of Japan, known for its port, thermal power stations, and the Kashiwazaki-Kariwa Nuclear Power Plant, the largest in the world. The code covers the city proper and adjacent towns, including parts of the former Kariwa and Nishiyama areas.

Dialing Formats

When dialing a number in Kashiwazaki from within Japan, you must include the area code, which begins with '0'. The local subscriber number is typically 6 digits long, making the total national significant number (NSN) 10 digits when including the area code. The format is: 02573-XX-XXXX (where X represents a digit). For example, a local number might be 02573-12-3456.

From outside Japan, callers must use the international prefix (e.g., 011 from the US, 00 from most countries), followed by Japan's country code +81, and then the area code without the leading '0'. Thus, the international format becomes: +81 2573-XX-XXXX. For instance, to call the same number from abroad, you would dial +81 2573 12 3456.

Caller Instructions

Local callers within the Kashiwazaki area can often dial the 6-digit subscriber number without the area code, depending on the specific local dialing plan. However, for clarity and to avoid misdialing, it is recommended to always include the area code, especially since Japan has implemented number portability and overlay plans in some regions.

Long-distance callers from other parts of Japan must dial the area code (including the leading '0') followed by the subscriber number. International callers must drop the leading '0' and use the +81 country code.

Overlay and Numbering Considerations

Currently, there is no overlay code for 2573; it remains the sole geographic code for this region. However, the Japanese Ministry of Internal Affairs and Communications (MIC) periodically reviews numbering resources. Subscribers in this area may have migrated to VoIP services, which can affect number portability but not the geographic significance of the code.

For businesses and residents, it is essential to display numbers in international format (+81 2573...) on websites and global directories to facilitate calls from overseas partners and customers.