Area Code 1397 – Okushiri, Hokkaido

Overview of Area Code 1397

Area code 1397 is a geographic National Destination Code (NDC) within the Japanese telephone numbering plan, specifically assigned to the town of Okushiri on Okushiri Island, located in the Hokkaido prefecture. This code is part of the broader 01397 numbering area, which historically served the Hiyama Subprefecture region. The island lies in the Sea of Japan, west of the Oshima Peninsula, and is known for its rugged coastline and fishing industry.

Geographic Coverage and Administrative Jurisdiction

The 1397 area code covers the entire municipality of Okushiri, which is the only town on the island. Administratively, it falls under the Hiyama Subprefecture of Hokkaido. The code is used for fixed-line PSTN services, including residential and business lines, and is managed by NTT East (Nippon Telegraph and Telephone East). The numbering area is geographically isolated, with all calls to the island routed through submarine cables from the mainland.

Dialing Formats and Procedures

For local callers within the same area code (1397), the subscriber number is typically 7 digits, and local calls are made by dialing the 7-digit number directly without the area code. However, for calls from other regions within Japan, the full national number must be dialed: 01397-XXXXXX (where X represents the subscriber number). For international callers, the format is +81 1397-XXXXXX (or +81 1397 XXXXXX). Note that the leading zero is dropped when dialing from abroad.

Overlay and Numbering Considerations

There are no overlay codes in this area; 1397 is the sole area code for Okushiri. The subscriber number length is 7 digits, which is standard for Japanese fixed-line numbers. As of the latest numbering plan updates, there are no plans for code changes or overlay introductions. The code is exclusively geographic, meaning it does not support number portability to mobile networks, but fixed-line number portability is available within the same service area.

Caller Instructions

For local callers within Okushiri: simply dial the 7-digit subscriber number. For callers from other parts of Japan: dial 01397 followed by the subscriber number. For international callers: dial the international access code (e.g., 011 from the US), then 81 (Japan's country code), then 1397 (without the leading zero), and finally the 7-digit subscriber number. Example: if the subscriber number is 1234567, an international caller would dial +81 1397 1234567.

Understanding these dialing procedures ensures seamless connectivity to Okushiri, whether for business or personal communication.