Japan phone number validator
How the phone number format works
- Format
- Japan phone number in national or international (+81) format
- Example
- +819012345678
Things to watch for
- Accepts national or international (E.164, e.g. +81...) format
- Validated with Google's libphonenumber; confirms the number is possible/valid for this country, not that it is currently assigned or reachable
^[+]?[0-9 ()\-]{6,}$A Japanese phone number splits by prefix: mobiles start with 070, 080, or 090 followed by eight more digits (090-1234-5678, 11 digits nationally), while landlines pair a regional area code — 03 for Tokyo, 06 for Osaka — with a local number. Both drop their leading 0 for +81, but because a mobile prefix (070/080/090) is three digits against a landline’s often shorter area code, the two end up different lengths internationally: ten digits after +81 for mobile, commonly nine for landline.
How this validator works
Type the number as dialled locally (090-1234-5678) or in full international form (+819012345678); this tool checks the digit count and the mobile prefix or area code against Japan’s real numbering plan using Google’s libphonenumber, entirely in your browser. The most frequent slip here is leaving the 0 attached after +81 — typing +81090-1234-5678 instead of +819012345678 — which adds a digit and fails validation immediately.
What a pass doesn’t tell you
A pass confirms the number matches a genuine Japanese mobile or landline shape — it doesn’t confirm the SIM is topped up or the landline connected. A well-formed number is not proof it reaches anyone today.
Scope: useful for catching a leftover 0 after +81, a wrong mobile prefix, or a missing digit before a Japanese number reaches a form or SMS platform — not a live reachability check.
Content last reviewed 2026-07-07.
phone number FAQ
How many digits does a Japanese mobile number have internationally?
Ten, after the leading 0 in 090-1234-5678 is dropped for +81 — the correct international form is +819012345678, keeping the 90 that follows the stripped 0, not +81901234-5678 with the 0 still attached.
How is a landline different from a mobile number in Japan?
A landline pairs a regional area code (03 Tokyo, 06 Osaka) with a shorter local number, and after dropping the leading 0 it ends up nine digits after +81 — one digit shorter than a mobile number's ten, since mobile prefixes (070/080/090) take up more of the total length than most area codes.
Does a valid Japanese number check mean it's currently in service?
No. It confirms the digits match a real Japanese mobile or landline pattern under the numbering plan the Ministry of Internal Affairs and Communications maintains — not that the SIM is active or the line connected, which needs a carrier-side check.