The easiest way to look up an area code is to enter the number in the search box - the region and the user reports for that number are shown together. To browse by region, use the area code list; to confirm the official assignment, use the MIC's "Telecommunications Number Designation Status." The steps for all three methods are explained below.
What Is an Area Code?
An area code is the leading portion of a landline phone number that indicates the caller's region. The MIC manages regional assignments, so you can identify the approximate origin just by looking at the number. Knowing how to look up area codes helps you quickly judge where a call is coming from when you receive a call from an unknown number, which is also useful for dealing with nuisance calls.
Area codes start with "0," which is a domestic prefix indicating a domestic call. For international calls, this 0 is dropped and replaced with the country code +81. In Japan's phone number system, the mapping between area codes and numbering zones is set out in the appended tables of the MIC Telecommunications Numbering Plan.
History and Origins of Area Codes
Japan's area code system took shape as the national telephone network moved to automatic dialing. Before that, long-distance calls required a manual operator, resulting in long wait times. Area codes were introduced to assign unique numbers to each region so calls could be connected automatically nationwide.
Initially, digit lengths were determined based on projected subscriber counts - major cities like Tokyo and Osaka received short 2-digit codes, while rural areas were assigned 4- or 5-digit codes. The area code and the local exchange number are combined so that the total is always 10 digits, a structure the MIC Telecommunications Numbering Plan still specifies. Mobile phones and IP phones (basics and benefits) later made the overall numbering system more complex, but a landline area code is still a 0 followed by 1 to 4 digits.
Major City Area Code List
Each major Japanese city has its own assigned area code. Here are representative examples:
- 03: Tokyo 23 wards
- 06: Osaka City (western Japan's economic center)
- 011: Sapporo (Hokkaido's central city)
- 022: Sendai (Tohoku's hub)
- 052: Nagoya (Chubu's center)
- 075: Kyoto (historic cultural capital)
- 078: Kobe (international port city)
- 092: Fukuoka (Kyushu's economic hub)
- 045: Yokohama (capital of Kanagawa Prefecture)
- 048: Saitama (Saitama Prefecture capital)
- 043: Chiba (Chiba Prefecture capital)
- 082: Hiroshima (Chugoku's central city)
- 096: Kumamoto (central Kyushu hub)
- 099: Kagoshima (southern Kyushu's central city)
Beyond these, hundreds of area codes exist across Japan. Area codes and their numbering zones are listed in the appended tables of the MIC Telecommunications Numbering Plan.
Watch Out for Nuisance Calls from Area Code 048
Area code 048 is assigned across a wide stretch of Saitama Prefecture, from southern cities such as Saitama, Kawaguchi, Toda and Warabi to northern ones such as Gyoda, Fukaya and Hanyu. Because a single area code covers that many municipalities, seeing 048 at the start of a number tells you nothing about which city or ward the call came from.
When an 048 number you do not recognize calls, search the number on this site first and check whether it has been reported as a nuisance call. Banks, hospitals and local government offices use numbers in the same range, so judge each number on its own instead of blocking a whole area code. If nuisance calls from the range keep coming, consider call blocking settings or reporting the number.
Area Code Digit Lengths and Structure
Japanese landline numbers consist of three elements - area code, local exchange number, and subscriber number - always totaling exactly 10 digits. Area code length varies from 2 to 5 digits depending on the region's subscriber count, with shorter area codes paired with longer local exchange numbers.
2-Digit Area Codes
Assigned to major cities with the most subscribers, such as Tokyo (03) and Osaka (06). The local exchange number is 4 digits and the subscriber number is 4 digits, totaling 10. The appended tables of the MIC Telecommunications Numbering Plan list three 2-digit area codes: 03 (Tokyo's 23 wards), 04 (areas such as Tokorozawa in Saitama and Kashiwa in Chiba), and 06 (Osaka City).
3-Digit Area Codes
Common among designated cities like Yokohama (045), Nagoya (052), and Sapporo (011). The local exchange is 3 digits and the subscriber number is 4 digits. The plan lists more than 40 three-digit area codes, mostly for prefectural capitals and other areas with many subscribers.
4-Digit Area Codes
Used for regional cities and mid-sized municipalities. Examples include 0422 (Musashino), 0798 (Nishinomiya), and 0985 (Miyazaki). The local exchange is 2 digits and the subscriber number is 4 digits. This is the most common area code length, covering hundreds of regions.
5-Digit Area Codes
Used for remote islands and mountainous areas with few subscribers, such as 04992 (Hachijojima) and 04998 (Ogasawara). The local exchange is 1 digit and the subscriber number is 4 digits.
Regional Classification by Leading Digit
You can identify the general region by looking at the digit following the leading 0. Memorizing this pattern lets you instantly estimate where an unknown call originates.
| Leading digits | General region | Representative area codes |
|---|---|---|
| 01 | Hokkaido | 011 Sapporo, 0138 Hakodate, 0166 Asahikawa |
| 02 | Tohoku, Niigata, Nagano | 022 Sendai, 023 Yamagata, 024 Fukushima, 025 Niigata, 026 Nagano |
| 03 | Tokyo 23 wards | 03 (shared across the 23 wards) |
| 04 | Western Tokyo, Chiba, Saitama, Kanagawa | 04 Tokorozawa, 042 Hachioji, 043 Chiba, 045 Yokohama, 048 Saitama |
| 05 | Chubu, Tokai, Yamanashi | 052 Nagoya, 053 Hamamatsu, 054 Shizuoka, 055 Kofu, 058 Gifu |
| 06 | Osaka City | 06 (shared across the city) |
| 07 | Kinki | 072 Sakai, 075 Kyoto, 077 Otsu, 078 Kobe |
| 08 | Chugoku and Shikoku | 082 Hiroshima, 083 Shimonoseki, 086 Okayama, 087 Takamatsu |
| 09 | Kyushu and Okinawa | 092 Fukuoka, 093 Kitakyushu, 096 Kumamoto, 098 Naha |
This classification is not absolute - some exceptions exist. For instance, the 02 band covers not only the six Tohoku prefectures but also Niigata (025 Niigata) and Nagano (026 Nagano), and the 05 band includes Yamanashi (055 Kofu). To pinpoint the exact region, you need to check the full area code.
How to Look Up Area Codes - Practical Steps
When you receive a call from an unknown landline number, follow these steps to identify the caller's region.
Step 1: Isolate the Area Code
Identify the area code from the beginning of the number. Major city 2-digit codes (03, 06) are instantly recognizable, but for 3+ digit codes you need to know the exact boundary. For example, 042 and 0422 refer to different regions, so determining the correct digit count matters.
Step 2: Search the Number on This Site
Enter the phone number into our search feature to see the region for that number and the reports other users have submitted. If the number has been reported as a sales or nuisance call, you can also read other users' experiences.
Step 3: Verify with the MIC Database
The MIC's "Telecommunications Number Designation Status" page publishes official allocation information for each area code. You can confirm which carrier is assigned to which number band - the most authoritative source available.
Step 4: Check Safety Before Calling Back
If you have a missed call, make it a habit to search the number before calling back. Avoid returning calls to numbers with numerous nuisance reports. If the caller is a legitimate business, call back using the official number listed on their website instead.
Points to Watch When Reading an Area Code
With IP phones, the area code alone may not pinpoint the caller's actual location. IP phone services like NTT's Hikari Denwa may use area codes that differ from the actual physical location. For example, a company physically located in Yokohama can technically obtain and use a Tokyo 03 number.
Caller ID spoofing (spoofing) can also make the displayed area code differ from the actual origin. Fraud groups have been reported spoofing government agency area codes. It is dangerous to judge a call's legitimacy based solely on the area code. If you receive a suspicious call, do not call back the displayed number - instead, contact the organization directly using the official number from their website or documents.
The PSTN to IP network migration was completed in January 2025, but area codes and their numbering zones remain defined in the appended tables of the MIC Telecommunications Numbering Plan. Because arrangements such as number portability (carrying a number over) change which carrier holds a number, check the full area code together with user reports rather than judging by the area code alone.