Area Code 144 – Tomakomai, Hokkaido

Overview of Area Code 144

Area code 144 is a geographic numbering plan area within the Japanese telecommunications network, serving the city of Tomakomai and its surrounding municipalities in the southern part of Hokkaido, Japan's northernmost main island. This code is part of the ITU-T E.164 numbering plan for Japan (country code +81) and is administered by the Ministry of Internal Affairs and Communications (MIC) under the country's closed dialing plan.

Geographic Coverage and Administrative Jurisdiction

The 144 area code covers Tomakomai City, which is the second-largest city in Hokkaido's Iburi Subprefecture. It also includes the neighboring towns of Abira and Atsuma, as well as parts of the wider coastal region facing the Pacific Ocean. Tomakomai serves as a major industrial and port city, hosting the Tomakomai Port and several large manufacturing facilities. The area is also known for its proximity to Lake Utonai and the scenic landscapes of southern Hokkaido.

Dialing Formats and Instructions

Within Japan, calls to numbers in the 144 area code must be dialed using the full 10-digit national number, which includes the leading '0' trunk prefix. For example, to call a local number such as 45-6789 within Tomakomai, you would dial 0144-45-6789 from any other part of Japan. The '0' is used to access the national trunk network, and the following '144' is the area code. When dialing from abroad, the leading '0' is omitted, and the country code for Japan (+81) is used. Thus, the same number would be dialed as +81 144-45-6789 from an international location.

It is important to note that Japan uses a closed numbering plan, meaning that local calls within the same area code still require dialing the full 10-digit number, including the area code. There are no separate local dialing formats; all calls, even within Tomakomai, must include the area code.

Overlay Considerations and Numbering Resources

Currently, there is no overlay code for the 144 area. The area code is exclusively assigned to geographic fixed-line services, including PSTN and VoIP services that are tied to a physical address within the coverage area. Mobile phone numbers in Japan are assigned to non-geographic prefixes (e.g., 070, 080, 090) and are not related to area codes. When calling a mobile number from Tomakomai, you would simply dial the 11-digit mobile number starting with 0, such as 090-1234-5678.

Number portability is available in Japan, allowing users to retain their fixed-line numbers when switching service providers within the same geographic area. However, porting a number outside the 144 area code is generally not permitted, as the number is tied to the geographic location.

Caller Instructions

For local callers within the 144 area, dial the full 10-digit number (e.g., 0144-45-6789). For callers from other parts of Japan, the same format applies. For international callers, replace the leading '0' with '+81' and omit the '0' when dialing from a mobile phone or using international dialing codes. Always ensure you have the correct country code and area code to avoid misdialing.