Wi-Fi Column: Staying connected in Japan

Free Wi-Fi related services available in times of disaster

This article was translated from Japanese to English using AI. Click here to view the original article (in Japanese).

Food, power, warm clothing - are you prepared for disaster? When the time comes, it's not just what's in your disaster bag that will help. There are also preparedness tips to remember and know.

During a disaster, internet connectivity can be difficult due to the concentration of phone calls and mobile communications. Free Wi-Fi also plays a role as a means of communication in such emergencies. In this article, we summarise how Wi-Fi can be useful in times of disaster.

  1. Free Wi-Fi "disaster mode", open in times of emergency
  2. 00000JAPAN (Five Zero Japan), a public wireless LAN service in times of disaster
  3. Minimum security measures in times of emergency
  4. Knowing about free Wi-Fi" preparedness

Free Wi-Fi "disaster mode", open in times of emergency

Some of the free Wi-Fi you use on a regular basis switches to 'disaster mode' in the event of an emergency, such as when a disaster occurs. The difference between this mode and normal mode is that it can be used immediately without having to register, for example, by entering an email address. It is precisely in times of disaster that you want to be able to use the internet quickly to gather information and communicate about your safety. It is best not to use it, but please keep it in mind in case of emergency.


The usage in 'Disaster Mode' is almost the same as in Normal Mode. If you use free Wi-Fi on a regular basis, you can use it smoothly in Disaster Mode. For basic information on how to use free Wi-Fi, please refer to the following article.

Basic Usage of Free Wi-Fi - And Tips for Safe Use

00000JAPAN (Five Zero Japan), a public wireless LAN service in times of disaster

Remember the term "00000JAPAN (Five Zero Japan)". This is one of the emergency services. The idea is that Wi-Fi spots normally used for carrier subscribers are changed so that anyone can use them only in an emergency.

Even Wi-Fi spots that cannot be used without a contract with a mobile carrier, such as docomo, au or Softbank, will be opened up for use by anyone, if necessary, under the unified network name (SSID) "00000JAPAN".

It may be opened not only during deserters, but also during mobile carrier outages, so look for it if you have problems.

It is not difficult to use. Simply tap "00000JAPAN" when you find it in the network list on the Wi-Fi screen of your device. You can connect without entering a password or registering an email address.


What is 00000JAPAN (Five Zero Japan)? -Public wireless LAN service in case of disaster or communication failure

However, 00000JAPAN does not have user authentication such as encryption or user registration. Therefore, it is necessary to be more careful about spoofed Wi-Fi set up by malicious third parties. However, it is very difficult to determine whether a Wi-Fi is spoofed or not. Think of it as emergency Wi-Fi and keep it to a minimum to confirm your safety and gather information.

Minimum security measures in times of emergency

Because free Wi-Fi is free for everyone to use, there are certain points to be aware of. However, when a disaster actually occurs, it is difficult to have the time to think about it or the time to relax.

To avoid unnecessary trouble in times of emergency, there are three points to keep in mind to ensure safe and secure use.

  • Only use Wi-Fi that is legitimately provided
  • Only visit sites beginning with "https"
  • Refrain from exchanging personal information

This is an emergency and there may be unavoidable circumstances. As far as possible, take care to use these three points. The following article explains them in more detail.


Also, in some places, such as shelters, communications can be busy. Everyone will be having an uncomfortable time. Try to be considerate when there is congestion and avoid using large amounts of data or using it for long periods of time.

Knowing about free Wi-Fi" preparedness

It is important to be aware of services and municipal Wi-Fi infrastructure that can be useful in the event of a disaster. For example, did you know that approximately 500 public telephones in Tokyo are equipped with Wi-Fi access points? In fact, these public telephones are also equipped with UPS (uninterruptible power supply) along with access points, so that free Wi-Fi can be used even during power outages.

In recent years, free Wi-Fi has become a familiar sight throughout the city, not only for everyday convenience but also as a disaster-prevention measure. It can be a great help in times of disaster.

It is difficult to think about this and that after a disaster. It is a good idea to familiarise yourself with free Wi-Fi in your immediate surroundings on a regular basis, as it will help you to be prepared in case of an emergency.

Basic Usage of Free Wi-Fi - And Tips for Safe Use

フリーWi-Fiスポットの探し方 ~見えない電波を捕まえろ!

In this article we have mainly told you about free Wi-Fi in emergencies. However, Wi-Fi is not the only point to be aware of when using the internet during a disaster.

Smartphone battery protection is essential. You will also need to take measures against the flood of fake news.

Sony Network Communication "令和版【ネットの防災マニュアル】Reiwa ver. Internet Disaster Prevention Manual" provides an easy-to-understand overview of disaster internet use, including the use of free Wi-Fi. Please take a look at it for reference.

令和版【ネットの防災マニュアル】いざという時のインターネットの使い方 | サステナビリティ | Sony Network Communications

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