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How to Block International Spam Calls

About 11 min read

The Rise of International Spam Calls

Spam calls from international numbers are increasing year over year, and complaints to the MIC continue to climb. The spread of VoIP technology has slashed the cost of calling Japan from overseas, and auto-dialing systems can blast tens of thousands of international calls per day at minimal expense - making Japan an attractive target for overseas fraud rings. One-ring scams combined with international call fraud are also on the rise. See also How to Spot and Stop Robocalls.

Types of International Spam Calls

International One-Ring Scams

The most common tactic is the international one-ring scam. An unfamiliar country code rings once and hangs up, luring you into calling back a premium-rate number that charges hundreds to thousands of yen per minute. African and Pacific island country codes (+222 Mauritania, +675 Papua New Guinea, +260 Zambia, etc.) are frequently reported.

Automated Voice Scam Calls

An international number rings and plays a recorded message: "Your account has been frozen," "You have unpaid charges," or "There is a problem with your visa." The goal is to extract personal information or money. Messages are often in English or Chinese, though Japanese versions are increasing.

Tactics by Country

Country codeMain tacticTypical scriptWhat to do
+1 US and CanadaRobocall scams impersonating the IRS or the Social Security Administration, with cases targeting Japanese residents in the US"You have unpaid taxes," "There is a problem with your Social Security number"Never respond to the recording; hang up and block the number
+44 UKInvestment fraud and lottery scams"You have won a large prize," "We have a special investment opportunity"Do not pay anything requested as a processing fee or tax
+86 ChinaEmbassy scams targeting Chinese nationals in Japan, impersonating the Chinese embassy or public security bureau, mostly as Chinese-language recordings"You are involved in a crime," "There is a problem with your passport"Hang up without paying, however threatening the call is; consult the Consumer Hotline at 188 if you are worried
+91 IndiaTech support scams impersonating Microsoft or Apple"Your computer is infected with a virus"Never grant remote access and never sign up for paid support
African nations such as +222, +232, +252One-ring scams that run up huge call chargesThe phone rings once and only a missed call remainsDo not call back; the return call connects to a premium-rate number charging hundreds to thousands of yen per minute
Pacific island nations such as +675, +676, +677The same one-ring scams as in African nations, aimed at regions where calls from Japan are expensiveAlso leaves nothing but a missed callDo not call back, and consider your carrier's international call blocking service

How to Block International Spam Calls

iPhone

  • Silence Unknown Callers: Settings > Phone > Silence Unknown Callers. Sends all non-contact calls - including international ones - to voicemail.
  • Block individual numbers: Tap the international number in your call history and select "Block this Caller."
  • Focus mode: Set to "Contacts Only" to block all unregistered international numbers.

Android

  • Google Phone app spam filter: Settings > Spam > Enable spam filtering. Works for international numbers too.
  • Block numbers: Long-press the number in call history and select "Block number."
  • Silent mode: Set to "Contacts Only" to block unknown international numbers.

Carrier International Call Blocking

  • NTT docomo: Contact docomo Information Center (151) to restrict international call reception.
  • au: "International Call Restriction" via My au or au shops.
  • SoftBank: "International Call Restriction" via My SoftBank or in-store.

Spam Filter Apps

Spam filter apps with global databases detect and block known international scam numbers in real time.

Never Call Back - Here's Why

Never return a call to an unknown international number. Installing a blocking app to auto-screen unknown international numbers is also effective.

  • Massive charges: Premium-rate numbers can cost hundreds to thousands of yen per minute. Automated messages keep you on the line while charges pile up.
  • Number harvesting: Calling back confirms your number is active, inviting more spam.
  • Direct connection to scammers: The callback number may be a fraud ring's front desk.

If You Have Contacts Abroad

Save their numbers in your phone so their calls come through normally while unknown international numbers are blocked. Encourage overseas contacts to use messaging apps like LINE or WhatsApp instead of international calls.

What to Do If You've Been Targeted

  • Contact your carrier: Explain the situation. Fraud-related charges may be reduced or waived.
  • Restrict outgoing international calls: Ask your carrier to add this restriction to prevent recurrence.
  • File a police report: See Phone Scam Reporting Guide and call #9110.
  • Consumer Hotline (188): Get advice from your nearest consumer affairs center.

Understanding International Call Rates

Rates vary dramatically by destination. Calls to the US or Europe cost tens of yen per minute, but calls to Africa or Pacific islands can reach hundreds of yen. Premium-rate numbers are even more expensive. Never call back an unfamiliar international number. See also How to Spot International Call Scams. Phone scam tactics grow more sophisticated every year, so staying informed is essential.

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Frequently Asked Questions

What should I do if I called back an unknown international number?

Hang up immediately and contact your carrier to explain the situation. Check your call records for unusually high charges. If the carrier recognizes it as fraud, charges may be reduced or waived. Ask them to add an outgoing international call restriction to prevent recurrence.

Can I block all international calls at once?

Yes. Use your carrier's 'International Call Restriction' service to block all incoming international calls. Smartphone features like 'Silence Unknown Callers' or Do Not Disturb set to 'Contacts Only' also work. Whitelist any overseas contacts you need to hear from.

Which country codes are most associated with one-ring scams?

African nations (+222 Mauritania, +232 Sierra Leone, +252 Somalia) and Pacific island nations (+675 Papua New Guinea, +676 Tonga) are frequently reported. International call rates to these regions are very high, so never call back an unfamiliar country code.

Why are there so many spam calls from +86 (China)?

The main cause is embassy scams targeting Chinese nationals living in Japan. Callers impersonate the Chinese embassy or public security bureau using Chinese-language robocalls, threatening victims with fabricated criminal charges or passport issues. If you don't speak Chinese, you can safely ignore these calls, but blocking the number is recommended.

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