Area Code 242 – Aizuwakamatsu, Fukushima

Geographic Coverage and Administrative Jurisdiction

The +81 242 area code is a geographic National Destination Code (NDC) assigned to the Aizu region in the western part of Fukushima Prefecture, Japan. This region is administered under the broader Tohoku (Northeast) telecommunications zone. The primary city served is Aizuwakamatsu, a historic castle town and the commercial center of the Aizu Basin. Other municipalities covered by this code include Aizubange, Koriyama (a portion), Shimogo, Minamiaizu, and the surrounding towns and villages that fall within the Aizu region. The area code 242 is distinct from the neighboring 241 (which serves the Koriyama area) and 243 (which serves the Shirakawa area), ensuring clear routing within the prefecture.

Dialing Formats and Number Structure

When dialing a landline number in the Aizuwakamatsu area, the local number consists of the area code 242 followed by a subscriber number of 4 to 5 digits, resulting in a total national significant number length of 9 to 10 digits (including the leading 0). For example, a typical local number might be (0242) XX-XXXX. To call from within Japan, you must dial the trunk prefix 0, then the area code 242, and then the subscriber number: 0242-XX-XXXX. 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: +81 242 XX-XXXX. For instance, a call to a number in Aizuwakamatsu would be dialed as +81 242 XX-XXXX.

Overlay Considerations and Local Calling

Currently, there is no overlay code for the 242 area; the region uses a single area code. However, as with many Japanese geographic codes, the number of available lines is sufficient for the population density. For local callers within the same area code, dialing the subscriber number without the area code is not permitted; all calls must include the area code, even for local calls, due to the Japanese numbering plan's requirement for closed dialing in most regions. This ensures that calls are routed correctly, especially in areas where mobile and VoIP numbers may be intermingled.

Caller Instructions and International Dialing

For international callers, it is essential to drop the leading 0 from the area code when dialing from abroad. For example, a call to a business in Aizuwakamatsu with the local number 0242-55-1234 would be dialed as +81 242 55 1234. For callers within Japan, the full 10-digit number (including the 0) is always required. This area code is used exclusively for fixed-line services, including PSTN and some VoIP services that are assigned geographic numbers. Mobile numbers in Japan begin with 070, 080, or 090 and are not tied to geographic regions, so they are not affected by this area code.