Mobile internet and connectivity in Japan

Many European and international mobile contracts include roaming packages for Japan, which require no setup but can be expensive for heavy data use. Travel eSIMs, bought online before departure and installed by QR code, have become the most common solution for travellers with recent smartphones: they offer data-only plans for a set number of days and gigabytes, while the home SIM stays active for calls and messages.

An eSIM needs a phone that supports it and is not locked to the home carrier. It is sensible to install it before departure and activate data on arrival.

Physical prepaid data SIM cards for visitors are sold at airports, electronics stores and online, for delivery to the hotel or pick-up at the airport. They provide data only; SIM cards with a Japanese phone number require residence registration and are not available to short-term visitors.

A pocket Wi-Fi router, rented for the duration of the stay, connects several devices at once and suits families or groups. Routers are collected at airport counters or delivered to the first hotel and returned by post or at the airport. The drawback is carrying and charging an extra device.

Free Wi-Fi is available at airports, major railway stations, many Shinkansen trains, convenience stores, chain cafés, hotels and tourist information centres, and many municipalities run their own networks for visitors. Registration by e-mail or social media account is often required, and connections can be slow or time-limited. Free Wi-Fi is a useful supplement, but not a reliable substitute for mobile data.

Japan's Radio Act normally requires wireless devices to carry Japanese technical certification. A special provision allows visitors to use phones, laptops and similar Wi-Fi and Bluetooth devices certified under certain foreign standards for a limited period after entry, which covers the usual smartphones, tablets and laptops brought by tourists.

Japanese sockets take type A plugs with two flat parallel pins, like those in North America; some sockets, especially in older buildings, do not accept polarised plugs with one wider pin. Visitors from continental Europe, the United Kingdom and Australia need a plug adapter.

The mains voltage is 100 volts. Most phone and laptop chargers are rated for 100–240 volts and work without a converter, but some hair dryers, kettles and other heating appliances designed for 230 volts will not work properly. The frequency is 50 hertz in eastern Japan, including Tokyo and Tohoku, and 60 hertz in western Japan, including Nagoya, Osaka and Kyushu, a legacy of the generators imported from Germany and the United States in the Meiji era; it matters only for a few older appliances.

Route planners and map apps with Japanese rail timetables are the most useful tools for getting around. Translation apps with camera functions help with menus and signs. The Japan Tourism Agency's Safety Tips app sends alerts in English and other languages for earthquakes, tsunami warnings, weather warnings and heatstroke risk. Visit Japan Web handles the online registration for immigration and customs before arrival.