Random Japanese Phone Numbers

The Random Japanese Phone Number Generator creates realistically formatted but fake Japanese phone numbers — both mobile (070 / 080 / 090) and city landline numbers — that you can copy, download, or print. It runs entirely in your browser, with no account and nothing sent to a server.

The numbers follow real Japanese numbering conventions (correct prefixes, real city area codes, the right digit counts and hyphenation), so they look genuine and pass format checks — but they are randomly generated and are not real, assigned numbers. It's built for developers and QA testers who need sample data, designers who need believable placeholder values, and anyone filling forms or demos that expect a Japan-shaped phone number.

A Japanese phone number is a country-internal number that normally starts with a trunk 0. The generator builds each number from that structure:

• Mobile numbers use one of the three mobile prefixes Japan actually uses — 070, 080, or 090 — followed by 8 random digits, for a total of 11 digits (e.g. 090 1234 5678). The prefix is chosen at random for each number.
• Landline numbers start with a real city area code and add enough random local digits to reach the standard 10-digit total. Tokyo (03) and Osaka (06) use 2-digit codes plus 8 local digits; most other cities (Yokohama 045, Nagoya 052, Kyoto 075, Kobe 078, Fukuoka 092, Sapporo 011) use 3-digit codes plus 7 local digits; Nara (0742) uses a 4-digit code plus 6 local digits.

City area codes are grouped into regions you can filter by: Kanto (Tokyo, Yokohama, Kawasaki, Saitama, Chiba, Hachioji), Kansai (Osaka, Kyoto, Kobe, Sakai, Nara), Chubu (Nagoya, Shizuoka, Hamamatsu, Kanazawa, Niigata), and Kyushu (Fukuoka, Kitakyushu, Kumamoto, Kagoshima, Nagasaki). Choose All Japan and it draws from every city in the dataset, including Sapporo.

Two format options shape the output. Include +81 converts the number to international format by replacing the leading trunk 0 with the +81 country code — so Tokyo's 03… becomes +81 3… and a mobile 080… becomes +81 80…; turn it off for the domestic 0-prefixed form. Include Hyphens inserts the conventional separators — mobiles split prefix-XXXX-XXXX (e.g. 080-4912-7350) and landlines split into area code and local halves.

Every random digit comes from the browser's Web Crypto API (crypto.getRandomValues), not Math.random(), so the values are cryptographically random and well distributed. Nothing is calculated against a real subscriber database — these are pattern-correct fakes.

1. Pick a region — All Japan, Kanto, Kansai, Chubu, or Kyushu — to control which city area codes the landline numbers use. (Mobile numbers aren't tied to a city.)
2. Pick a phone type — All Types, Landline, or Mobile. "All Types" mixes both at roughly 50/50.
3. Set the format options — toggle Include +81 (international vs. domestic 0 form) and Include Hyphens (formatted vs. plain digits). Both are on by default.
4. Choose how many with the quantity slider (1 to 50, default 18).
5. Generate. With "Auto-generate on settings change" on (the default), the list refreshes whenever you change a setting; you can also click Generate Japanese Numbers, or Generate More to append another batch.
6. Use the results. Click any card (or its copy icon) to copy that number, or use Copy All, Download (a tab-separated .txt with Phone Number / City / Region / Type columns), or Print.

Worked example — 3 mobile numbers, international format. Set region All Japan, type Mobile, Include +81 on, Include Hyphens on, quantity 3. You get three numbers like +81 80-4912-7350, +81 90-2087-1164, and +81 70-6635-4928 — each a valid Japanese mobile prefix in +81 form with the leading 0 dropped, followed by 8 random digits. (Yours will differ; they're random.)

If you instead wanted a 10 digit Japanese dummy phone number for a Tokyo landline, choose Kanto, type Landline, turn Include +81 off, and you'd get something like 03-8421-9076 — the real Tokyo area code 03 plus 8 random local digits.

• Software testing & QA — populate sign-up forms, checkout flows, and CRM imports with believable Japan numbers to test validation, formatting, and storage without touching anyone's real number.
• Seed & demo data — fill a staging database or product demo with dozens of Japan-shaped contacts in one click via Download or Copy All.
• Form & placeholder data — supply a fake japan number when a form demands a +81-format or 10/11-digit value and you don't want to hand over a real one.
• Design & mockups — drop realistic numbers into UI comps, contact lists, or invoice and label templates so screenshots look authentic.
• Localization & i18n checks — verify your app accepts and displays Japanese mobile (11-digit) vs. landline (10-digit) numbers, with and without the +81 country code and hyphens.
• Teaching & documentation — show example numbers in tutorials or API docs without publishing a live line.

• These are not working numbers. Every value is randomly generated to look valid; it isn't checked against any carrier and almost certainly isn't assigned. Don't call or text them, and never use them to deceive.
• Mobile = 11 digits, landline = 10 digits. Japanese mobiles (070/080/090 + 8) are 11 digits in domestic form; landlines are 10. If your validator only accepts one length, pick the matching phone type.
• "+81" replaces the leading 0 — it isn't added on top. International format is +81 3-… / +81 80-…, not +81 0…. If your system expects the 0 kept, turn Include +81 off and use the domestic form.
• No dedicated Hokkaido filter. Sapporo (011) is in the data and appears under All Japan, but there's no Hokkaido region button. To bias toward Sapporo, generate from All Japan and pick it out.
• The city list is curated, not exhaustive. Landlines come from a fixed set of major cities per region (about two dozen total), so you won't see every Japanese area code — just realistic, well-known ones.
• Local digits are uniformly random. Real local numbers have exchange sub-ranges; this tool fills the local part with uniform random digits, so a number can be format-valid yet fall in an unallocated range. Ideal for testing, not for anything claiming to be real.
• Download is a tab-separated .txt, not .csv. The file (japanese-phone-numbers.txt) has a header row and four tab-delimited columns. If you need a CSV, import it as tab-delimited or convert after download.
• "Generate More" appends. Each click adds another batch of up to 50 to the existing list, so you can build a list well past 50 by clicking repeatedly.

Are these real Japanese phone numbers? No. They're randomly generated fakes that follow real Japanese formatting — correct mobile prefixes, real city area codes, and the right digit counts — so they look authentic and pass format checks, but they are not assigned, working numbers. Use them for testing and placeholders only.

How do I generate a Japanese mobile phone number specifically? Set the phone type to Mobile. Every result starts with 070, 080, or 090 and is 11 digits in domestic form (or +81 70/80/90 … with Include +81 on).

What's the difference between the landline and mobile output? Landlines use a real city area code (like Tokyo 03 or Kyoto 075) and total 10 digits; the region filter changes which cities appear. Mobiles use a 070/080/090 prefix, aren't tied to a city, and total 11 digits.

Can I get a plain 10-digit Japanese dummy phone number with no +81 and no dashes? Yes — choose Landline, turn off Include +81 and Include Hyphens, and you'll get an unbroken 10-digit string such as 0384219076.

Is anything I generate sent to a server? No. Generation happens entirely in your browser using the Web Crypto API, and copy, download, and print all run locally — the numbers never leave your device.