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Numbering Plan

A numbering plan defines telephone number structure (digits, format, purpose) and allocation rules. Japan's Ministry of Internal Affairs manages the "Telecommunications Numbering Plan," handling area code assignment, mobile number allocation, and special numbers like 0120/0570.

Japanese numbers follow "0 + area code + local code + subscriber number": 10 digits for landlines, 11 for mobiles (090/080/070 + 8 digits). This conforms to ITU-T E.164; international calls use country code "+81" dropping the leading 0.

Number exhaustion is critical. Mobile 090 numbers were exhausted in 1999, followed by 080 (2002) and 070 (2013) openings. With 070 exhaustion approaching, the Ministry is considering 060. 0120 exhaustion prompted 0800 introduction.

Plans evolve with society: MNP introduction, 050 number creation, and PSTN migration numbering reviews. See phone number structure guide and number length history.

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Related Terms

Area Code

A regional identification number at the beginning of a landline phone number. 03 indicates Tokyo's 23 wards, and 06 indicates Osaka City.

0120 Number

A toll-free number where the receiver pays call charges, widely used for corporate customer service lines.

050 Number

Numbers assigned to IP phones, not tied to geographic areas, obtainable at low cost but unable to make emergency calls.

MNP (Mobile Number Portability)

A system that allows switching carriers without changing your phone number. Introduced in Japan in 2006.

PSTN (Public Switched Telephone Network)

The traditional analog landline telephone network. Migration to IP networks has been underway since 2024.

Subscriber Number

The trailing portion of a phone number that identifies individual subscribers.

Related Articles

How Japanese Phone Numbers Work - From Area Codes to Mobile NumbersThe History of Phone Number Digit Lengths in Japan090, 080, and 070 Numbers - Differences and History
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