Frequently Asked Questions about Mobile Phone

All three are mobile phone number ranges, but they were introduced at different times.

• 090: the oldest mobile range, allocated since the 1999 switch to 11-digit numbering.
• 080: introduced around 2002 as the 090 pool started to run out.
• 070: originally reserved for PHS, then opened up to mobile phones in 2013.

There is no difference in call quality or service between these ranges.

Mobile Number Portability (MNP) lets you switch mobile carriers without changing your phone number. The system launched in Japan in 2006.

• Procedure: obtain an MNP reservation number from your current carrier, then sign up with the new one.
• Cost: porting-out fees have been free of charge since April 2021.
• Validity: MNP reservation numbers expire after 15 days.

Because of MNP, the carrier behind a number can no longer be identified from the number alone.

Because MNP is widespread, you usually cannot determine the current carrier from the number alone. However, you can check the original carrier assignment in the Ministry of Internal Affairs and Communications' telecommunications numbering allocation tables.

Ranges such as 090-1xxx-xxxx and 080-1xxx-xxxx were originally assigned to specific carriers, but the number may have since been ported, so treat this only as a rough indicator.

Here is a recommended approach for unknown mobile callers.

• Search the number on this site to read user reports.
• Check any voicemail message they may have left.
• If you must call back, consider doing so with caller ID withheld.
• If you suspect a scam, block the number on your phone.

Special-fraud schemes that target victims via mobile numbers are increasing, so do not call back unfamiliar numbers without checking first.

Japanese mobile numbers were extended from 10 to 11 digits on January 1, 1999, because rapid growth in mobile subscribers had exhausted the original number pool.

The 11-digit format provides roughly 90 million possible numbers in theory. Today the system uses three ranges - 090, 080, and 070 - and the future opening of a 060 range is also under discussion.