This is not a substitute for official information. Always follow announcements and evacuation orders from your city and the Japan Meteorological Agency.公式情報の代わりではありません。必ず自治体・気象庁の発表と避難指示に従ってください。
Japan disaster alerts in your language
Earthquakes, tsunamis, typhoons and heavy rain — official alerts explained in plain words, with the nearest evacuation sites and what to do now.
Latest alerts
Data updates are delayed. Please also check the official JMA website.データ更新が遅れています
Add your place in Settings to see alerts for your area.
Designated emergency evacuation sites from official data. Your location is used only on this device and is never sent to our server.
Source: GSI designated emergency evacuation sites (processed by BOSAI).
Check your city’s hazard map too — some sites are not safe for every kind of danger.
What to do
Short checklists for the first minutes. Read them now, before a disaster happens.
Japan’s 5 alert levels
Emergency go-bag checklist
Tick what you already have. Saved only on this device.
Settings
Alert notifications
Get a notification when an alert affects your places. Free: 1 place, shaking of intensity 5 Lower or stronger and warnings. Premium: up to 5 places and detailed settings.
Offline pack
Save evacuation sites and action cards so they work without internet.
Family board
Share “I’m safe” with your family in one tap, with your approximate location if you choose.
Emergency information is always free. Premium saves you effort when you look after several places and family members.
Monthly and yearly plans renew automatically until you cancel. Prices include tax.
About BOSAI
BOSAI (防災, “disaster prevention”) helps the more than three million foreign residents of Japan understand earthquake, tsunami, typhoon, heavy-rain, river-flood, landslide and volcano alerts. It reads the official disaster information published by the Japan Meteorological Agency (JMA) every minute and explains each new alert in 13 languages: what happened, where, and what to do now.
Numbers such as seismic intensity, wave height and times are copied from the official data by code; AI only rewrites the sentences. The original Japanese text and a link to JMA are always shown, because BOSAI is not a substitute for official information.
How to use
Open Alerts to see the latest official alerts in your language.
Open Shelters and tap “Use my location” to find the 5 nearest designated evacuation sites for the danger you choose.
Read What to do now — short checklists for an earthquake, a tsunami warning, an evacuation order and the day before a typhoon.
In Settings, save your place and turn on notifications. Add BOSAI to your home screen so it also works offline.
Frequently asked questions
Is BOSAI an official government service?
No. BOSAI rewrites official alerts from the Japan Meteorological Agency (JMA) in plain language. It is not a substitute for official information — always follow announcements and evacuation orders from your city and JMA.
Is it free?
Yes. The alert feed, summaries in 13 languages, evacuation sites, action cards and emergency numbers are always free. Optional Premium only adds convenience such as more saved places and a family board.
Does BOSAI send my location anywhere?
BOSAI never sends your location to its server. Nearest evacuation sites are calculated inside your browser, and for notifications only the prefecture you choose is stored. The map images are loaded from Japan’s GSI (Geospatial Information Authority), which can see the map area you view.
How are the summaries made? Can AI get the numbers wrong?
Numbers such as seismic intensity, wave height and times are copied by code from the official data. AI only rewrites the sentences, and a check rejects any summary containing a number that is not in the original. The original Japanese text is always shown too.
Does it work without internet?
Yes. BOSAI is an installable web app. The screens, action cards and the evacuation sites of the prefectures you viewed are saved on your device, and the last alerts stay visible offline.
What is the difference between 高齢者等避難 and 避難指示?
高齢者等避難 (Level 3) asks older people and anyone who needs more time to evacuate now. 避難指示 (Level 4) means everyone in the danger area must evacuate now. Do not wait for Level 5.
