Short answer. Japan warns the public through J-Alert (全国瞬時警報システム), run by the Fire and Disaster Management Agency 1. It relays ballistic-missile information, earthquake early warnings, major tsunami warnings and special weather warnings instantly to municipal outdoor loudspeakers and, since 1 April 2014 for civil protection, to mobile phones by emergency alert mail 23. A missile may arrive less than 10 minutes after launch 4.
How does J-Alert work?
Civil-protection information comes from the Cabinet Secretariat; weather and seismic information comes from the Japan Meteorological Agency 21. J-Alert automatically triggers municipal disaster-prevention radio (outdoor speakers) and sends Emergency Area Mail / emergency alert mail (緊急速報メール) to mobile phones in the affected area 23.
Is there a warning siren?
Yes. The government set a dedicated civil-protection warning siren tone in July 2005. Municipalities use it in principle when their area is under or facing armed attack. Reproducing or sounding it without cause is prohibited 3.
What do the missile messages mean?
| Message | Meaning |
|---|---|
| Missile launch (発射情報) | A missile may reach Japan: move inside a building or underground. |
| Impact forecast (落下予測情報) | Evacuate immediately; the expected time and prefecture of impact are given. |
| Interception (破壊措置情報) | The missile was destroyed; fragments may fall; stay indoors. |
| Impact estimate (落下推定情報) | The missile has fallen near a named place; stay indoors and wait for updates. |
| Overflight / all clear (通過情報・解除情報) | The evacuation call is lifted; do not approach suspicious objects; call police, fire or the coast guard. |
Source: Cabinet Secretariat 4. The launch message reads: 「ミサイル発射。ミサイル発射。北朝鮮からミサイルが発射されたものとみられます。建物の中、又は地下に避難して下さい。」 ("Missile launch. A missile appears to have been launched from North Korea. Take shelter inside a building or underground.") 4
What should I do when the alert comes?
- Outdoors: go into the nearest building, preferably concrete, or underground. If there is none, take cover or lie flat and protect your head 4.
- Indoors: move away from windows, ideally to a windowless room, and close the curtains 4.
- After the all-clear: do not approach suspicious objects; report them to the police, fire service or coast guard 4.
The nearest designated facilities are listed on the public shelters page. Phone numbers are on the emergency contacts page.
Are the systems tested?
Yes. A nationwide J-Alert information transmission test is run every quarter for all local governments, and all receivers are checked for continuity every month 5.
Is there an alert app for visitors?
Safety tips, supervised by the Japan Tourism Agency, sends push alerts for earthquake early warnings, tsunami warnings, special weather warnings, volcanic warnings, evacuation information and heatstroke information. The Japanese page lists 15 languages, the English page 14 67. Civil-protection (missile) alerts are not listed among its notifications, so do not rely on it alone for missile warnings. A battery radio helps when networks fail: see /guides/emergency-radio.
Frequently asked questions
How do missile alerts reach my phone?
Civil-protection information is sent by carrier emergency alert mail (緊急速報メール / Area Mail), in place since 1 April 2014 3.
How much warning time is there?
A missile may arrive less than 10 minutes after launch 4, so act on the first message.
What does the interception message mean for me?
The missile was destroyed but fragments may fall: stay indoors 4.
Does the Safety tips app send missile alerts?
Missile alerts are not listed among its notification types 67.
Sources
- 総務省消防庁 (FDMA) — 全国瞬時警報システム（Jアラート）の概要 — https://www.fdma.go.jp/about/organization/post-18.html (accessed 2026-10-20)
- 内閣官房 (Cabinet Secretariat) — Jアラート（全国瞬時警報システム）による情報伝達について — https://www.kokuminhogo.go.jp/kokuminaction/jalert.html (accessed 2026-10-20)
- 内閣官房 (Cabinet Secretariat) — 国民保護のための情報伝達の手段 — https://www.kokuminhogo.go.jp/gaiyou/shudan.html (accessed 2026-10-20)
- 内閣官房 (Cabinet Secretariat) — 弾道ミサイル飛来時の行動 — https://www.kokuminhogo.go.jp/kokuminaction/ (accessed 2026-10-20)
- 総務省消防庁 (FDMA) — 令和4年版 消防白書 2．Jアラートによる迅速な情報伝達 — https://www.fdma.go.jp/publication/hakusho/r4/chapter3/section1/30103.html (accessed 2026-10-20)
- 観光庁 (Japan Tourism Agency) — 訪日外国人旅行者用災害時に役立つツール — https://www.mlit.go.jp/kankocho/seisaku_seido/kihonkeikaku/jizoku_kankochi/anzenkakuho/inbound/tool.html (accessed 2026-10-20)
- Japan Tourism Agency — Information on illnesses, injuries, and disasters — https://www.mlit.go.jp/kankocho/en/shisaku/kokusai/traveltojapan.html (accessed 2026-10-20)
Turn this into action
Your plan for Japan, worked out for your household.
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- Phaenyx Safe: one tap to tell your people you are safe
Sources
- 総務省消防庁 (FDMA) · 全国瞬時警報システム（Jアラート）の概要 checked 2026-10-20
- 内閣官房 (Cabinet Secretariat) · Jアラート（全国瞬時警報システム）による情報伝達について checked 2026-10-20
- 内閣官房 (Cabinet Secretariat) · 国民保護のための情報伝達の手段 checked 2026-10-20
- 内閣官房 (Cabinet Secretariat) · 弾道ミサイル飛来時の行動 checked 2026-10-20
- 総務省消防庁 (FDMA) · 令和4年版 消防白書 2．Jアラートによる迅速な情報伝達 checked 2026-10-20
- 観光庁 (Japan Tourism Agency) · 訪日外国人旅行者用災害時に役立つツール checked 2026-10-20
- Japan Tourism Agency · Information on illnesses, injuries, and disasters checked 2026-10-20