Area Code 1366 – Suttsu, Hokkaido

Overview of Area Code 1366

Area code 1366 is a geographic National Destination Code (NDC) within the Japanese numbering plan, assigned to the town of Suttsu and its surrounding administrative district in the Shiribeshi Subprefecture of Hokkaido. This code is used for fixed-line (PSTN) services and is part of the broader Hokkaido telephone area, which is characterized by multiple smaller NDCs serving rural communities.

Geographic Coverage and Jurisdiction

The 1366 area code covers the town of Suttsu (寿都町) and adjacent localities along the western coast of Hokkaido, facing the Sea of Japan. The region is known for its fishing industry and scenic landscapes. Administratively, Suttsu is part of Shiribeshi Subprefecture, which also includes larger towns like Kutchan and Iwanai. The code is allocated to Nippon Telegraph and Telephone East (NTT East) for local exchange services.

Dialing Formats and Procedures

For local calls within the 1366 area, callers can dial the subscriber number without the area code, as is standard in Japan. However, for calls from outside the area (including from other parts of Japan), the full national format must be used: 0-1366-XX-XXXX. For example, a local number might be formatted as 0-1366-5-1234.

When calling from abroad, the international format is required: +81-1366-XX-XXXX (drop the leading zero). For instance, to call a number in Suttsu from the United States, you would dial 011-81-1366-XX-XXXX.

Overlay and Numbering Considerations

As of the latest ITU-T E.164 allocations, there is no overlay code for the 1366 area; it remains a standalone NDC. Subscriber numbers within this code typically have a variable length, often 4 to 5 digits after the area code, resulting in a total national significant number length of 10 digits (including the leading 0). The area code is not portable to mobile numbers, as mobile services in Japan use separate non-geographic prefixes (e.g., 070, 080, 090).

Caller Instructions

For callers within Japan: If you are dialing from outside the 1366 area, you must include the trunk prefix 0 and the area code. For example, from Tokyo, you would dial 0-1366-XX-XXXX. For callers outside Japan: Replace the leading 0 with the country code +81, and omit the trunk prefix. Always verify the local number length, as it may vary.

Given the rural nature of the region, some businesses may use VoIP services that appear under different NDCs, but traditional fixed-line numbers remain under 1366. For emergency services, dial 110 (police) or 119 (fire/ambulance) regardless of the area code.