·9 min read·Japan anti-spam act and sales email

Sending Cold Email Without Breaking Japan's Anti-Spam Act (2026)

Is B2B cold email illegal? A practical look at the opt-in exemption for businesses under Japan's Act on Specified Electronic Mail, required unsubscribe paths, and mandatory sender disclosures. Penalties (up to ¥30M for companies), how to stay clear of them, and a safe sending pace.

Related:is cold email illegalhow to send a sales emailsales email lawB2B cold email
Disclaimer
This article reflects information as of May 2026. For legal advice, consult an attorney.

"Does B2B cold email violate Japan's Act on Specified Electronic Mail?" The short answer: with a proper unsubscribe path and sender disclosure, it doesn't. There are only three points that matter.

Bottom line: businesses fall under the opt-in exemption, but three obligations apply

  1. 01
    State the sender (company name, address, contact) in the body
    Always include company info at the foot of the body. A sole proprietor may instead use "disclosed on request".
  2. 02
    State how to unsubscribe (opt out), and act within 3 business days
    A URL or an email reply. You must have a workflow that responds the moment a request comes in.
  3. 03
    Opt-in is required for individuals; there's an exemption for businesses
    For B2B — a corporate recipient — prior consent is not required for an email address published on an official site, etc. (Article 3, Paragraph 1, Item 3).

1. Information required in the sender disclosure

  • The sender's name or company name
  • An address (a sole proprietor may instead use "disclosed on request")
  • A point of contact (email or phone)
  • How to unsubscribe (URL or reply)
Example of a good sender disclosurefrom: support@example.co.jp
Toinfo@target.co.jp
SubjectA proposal regarding ___
(body)
Example Co., Ltd.
Shibuya-ku, Tokyo...
TEL: 03-xxxx-xxxx
Email: support@example.co.jp
Unsubscribe: https://example.co.jp/unsubscribe?token=xxx

2. The unsubscribe (opt-out) obligation

At the foot of the email body, clearly state "Unsubscribe here → URL" or "To unsubscribe, reply to this email". When a request comes in, you must, as a rule, complete the unsubscribe within 3 business days.

Even when sending as an individual, put "Unsubscribe: please reply" into your mail client's signature block and you'll never have to write it by hand again.

3. The B2B (business) exemption

The Act on Specified Electronic Mail is fundamentally a law protecting individuals, but Article 3, Paragraph 1, Item 3 specifies that prior consent is not required to send to "a corporation that has published its own email address". In other words, you may send to an email address listed on an official website as long as you satisfy obligations 1 and 2 above.

RecipientOpt-in required?Conditions
Individual (gmail.com, etc.)RequiredMay not send without prior consent
Business (email listed on an official site)Not requiredSender disclosure + unsubscribe path required
Business (email received on a business card)Not requiredB2B exemption, but unsubscribe path still required
Sole proprietor (with a trade name)Judgment variesTreated as a business if commercial intent is clear

A practical checklist

  1. Confirm the recipient is a business (or a sole proprietor's business address)
  2. Confirm the email address was obtained from public information (an official site, etc.)
  3. Confirm the sender disclosure and unsubscribe path are at the foot of the body
  4. Have a workflow ready to respond to replies within 3 business days
  5. Keep a separate "never send again" list for any address that requested an opt-out

How bacotto stays compliant

bacotto captures email addresses only from official sites and public information, which falls under sending to "a corporation that has published its own email address". The AI sales-copy generator automatically includes an unsubscribe path.

For opt-out management, it's common to add an "ng_emails" column to the CSV and manage it manually, or use the suppression-list feature of a sending tool (GMass, Lemlist, etc.).

Penalties for a violation

  • Failing to disclose sender info or ignoring unsubscribes → an administrative order → a fine of up to ¥1M (up to ¥30M for a company)
  • An ISP / sending provider cuts you off → your sending domain's reputation collapses
  • Blacklisting → it affects even your legitimate outreach afterward

Sending pace (a technical best practice)

A safe daily sending pace
50
A new domain
200
A domain over a year old
500
A warmed-up domain

To preserve your Gmail / Outlook reputation, avoid blasting from a new domain. A warm-up period (gradually ramping up volume) of 2-4 weeks is recommended.

Compliant AI sales copy in 3 minutes
Auto-inserted unsubscribe link / sender-disclosure template included
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