Area Code 270 – Isesaki, Gunma

Geographic Overview

The +81 270 area code is a geographic National Destination Code (NDC) assigned to the Isesaki area of Gunma Prefecture, Japan. This code covers Isesaki City and its surrounding municipalities, including parts of Ota, Tatebayashi, and Ora District. The region is located in the northern Kanto Plain, approximately 100 kilometers northwest of Tokyo, and is known for its industrial base, particularly in automobile manufacturing and textiles.

Dialing Formats

When dialing a number within the 270 area code from within Japan, you must include the leading '0' (trunk prefix). The local number format is 0-270-XX-XXXX (or 0270-XX-XXXX when written with the area code). For example, a local call to a landline in Isesaki would be dialed as 0270-XX-XXXX.

From outside Japan, callers must use the international access prefix (e.g., 011 from the US, 00 from most countries), followed by Japan's country code +81, then the area code without the leading zero, and the subscriber number. The international format is +81-270-XX-XXXX. For instance, if the local number is 0270-12-3456, an international caller would dial +81 270 12 3456.

Geographic Coverage and Overlays

The 270 area code serves a well-defined geographic region in southeastern Gunma Prefecture. It is not an overlay code; it is the sole area code for this region. However, adjacent areas use different codes: Maebashi uses 027, Takasaki uses 027, and Ota uses 276. This clear demarcation helps in routing calls efficiently.

Caller Instructions

• Local callers (within the 270 area): Dial the 7-digit subscriber number directly (without the area code). For example, to call 0270-12-3456 locally, dial 12-3456.
• Domestic long-distance callers (outside the 270 area): Dial 0-270-XX-XXXX (including the trunk prefix 0).
• International callers: Dial your country's exit code, then 81 270 XX XXXX (omit the leading 0 of the area code).

Numbering Plan Administration

Japan's numbering plan is administered by the Ministry of Internal Affairs and Communications (MIC) and allocated to carriers. The 270 area code is assigned to NTT East, the dominant fixed-line operator in the region. Since the liberalization of telecommunications, other carriers may also offer services using this code, but the geographic significance remains unchanged.

As with all geographic codes in Japan, numbers are portable within the same area code, meaning subscribers can switch carriers while keeping their number. However, number portability does not allow moving a number outside the 270 geographic area.