+81JP
Japan number screening
LINE dominates and WhatsApp barely registers. Portability killed prefix inference, and stray 050 IP numbers are the most common contaminant in Japanese lists.
Mobile number format
Japanese mobiles are 11 digits nationally, beginning 090, 080 or 070 — written 090-1234-5678. Drop the leading zero internationally: +81 plus 10 digits. 050 is an IP telephony range, not a mobile number, and it turns up in lists constantly.
Main carriers
- NTT Docomo
- KDDI (au)
- SoftBank
- Rakuten Mobile
Japan introduced number portability back in 2006, so 090/080/070 tells you only that the line is mobile — nothing about the operator. Add sub-brands like ahamo, povo and LINEMO plus a deep MVNO market of budget SIMs, and prefix-based carrier inference simply does not work here.
On the ground
Electronic advertising falls under the Act on Regulation of Transmission of Specified Electronic Mail, which requires prior opt-in as a rule, making unsolicited bulk sends riskier than in Southeast Asia. Consumers are also unreceptive to cold calls and unknown SMS, so the standard approach is to build the relationship on LINE or an e-commerce platform first. Logistics and support effectively stop over New Year and Obon.
Screening guidance
Strip 050 IP numbers and short rows first, then run validity plus a live carrier lookup, since portability has voided the prefix entirely. Base reachability on LINE, use Amazon to identify online shopping habits, and use iOS and X for profile layering. Do not make WhatsApp the primary gate — a low hit rate there says nothing about number quality.
Key platforms in Japan
LINE is the national messaging layer, and corporate outreach runs through LINE Official Accounts rather than SMS; WhatsApp has almost no presence, which is worth knowing before budgeting for it. X sees unusually intense use in Japan and iOS share is far above most markets, so both are unusually discriminating signals for profiling.
FAQ
How many digits is a Japanese mobile number, and how does it start?
Eleven digits nationally, opening 090, 080 or 070 — written as 090-1234-5678. Internationally, drop the leading zero: +81 plus 10 digits. 070 was originally the PHS range and was reassigned to mobile after PHS shut down, so it is a perfectly normal mobile prefix. Do not discard it as an anomaly during cleaning.
Are 070 and 050 the same thing in Japan?
No. 070 is a mobile range; 050 is IP telephony carried over internet voice services, usually bound to a softphone or office handset, with none of the SMS or account-registration behaviour of a mobile line. 050 numbers show up often in bulk lists, so separate them by prefix before you run validity checks at all.
Is screening WhatsApp worthwhile in Japan?
Of limited value. LINE is the national messenger and corporate outreach runs through LINE Official Accounts; WhatsApp penetration is far below other Asian markets, so using it as your quality yardstick will badly understate a list. Make LINE the primary signal and supplement with Amazon, iOS and X for audience profiling.
Start screening Japan numbers
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