Cell phone in Japan

Japan is a leader in mobile phone technology and usage with about 75% of the population owning one. Mobile phones are everywhere, and they are constantly getting new features such as internet browsers, games, cameras, televisions, electronic wallets/train passes, gps/navigation and music players.

The biggest mobile phone companies in Japan are NTT Docomo, au by KDDI, and Softbank (formerly Vodafone, and before that J-phone). Docomo is the most popular company with about 50 million subscribers. Au is next with about 30 million subscribers, while Softbank has about 15 million subscribers.

Due to different technologies, mobile phones from your home country may not work in Japan. Most importantly, there is no GSM network, so GSM phones do not work. There are two things that are required for your telephone to work:

1. Compatibility with the Japanese mobile phone network
- The only foreign phones that work in Japan are some 3G models, however the number of compatible phones is increasing. Contact your service provider for details concerning your particular phone.

2. International roaming plan or rental SIM card
- With an international roaming plan (from your home service provider) you use your own phone and number, but are charged international roaming rates which tend to be expensive. Alternatively, with a rental SIM card (from a Japanese provider) you use your own phone with a Japanese phone number and lower rates.

Many phones that are sold in Japan can operate on 3G and GSM networks (only in certain countries) with the appropriate international roaming plans, although while overseas some of their advanced functions will likely not work. This means that a person with a handset and service provided by a Japanese mobile phone carrier can roam when travelling outside of Japan.

Generally speaking it is not possible to use a Japanese phone with a foreign service provider due to network differences and because the handsets are locked. Japanese carriers do not unlock handsets. Also, Japanese phones are designed at a hardware and software level to work with only a particular network. As a result they are not interchangeable even between Japanese service providers and some of their features are disabled when used off of the network they were intended for.