Internet in Japan: why it pays to arrive already connected

Japan has one of the densest and most reliable mobile networks in the world. Coverage is not the problem anywhere: the problem, if you travel without preparing anything, is the paperwork.

Coverage, which is among the best

4G across virtually the whole country, wide 5G in the metropolitan areas and coverage in places you would not expect it: the Tokyo metro works underground, and the Shinkansen keeps signal along nearly the whole route, with the breaks you would expect in the long tunnels.

In mountain areas (the Japanese Alps, parts of Hokkaido) there are gaps, but far fewer than the terrain would suggest.

Why a local SIM is not the easy option here

Buying a line in Japan as a tourist is possible but not simple: a good share of contracts require residency, and the options for visitors are at specific airport counters with their own opening hours. Add the language, which outside the foreigner counters is a real barrier.

Portable router rental exists and is very widespread there, but it is one more device to charge, to return and not to lose.

That is why Japan is one of the destinations where arriving with the eSIM already installed changes the first day most: you walk out of Narita or Kansai with data and forget about the matter.

Public wi-fi, with caveats

There is plenty of free wi-fi in stations, convenience stores and cafes, but a good share asks for prior registration with an email address and some only work once you have installed an app. With your own data you skip that dance.

What you will use

Japan is a destination of maps and translation. Camera translation, used there constantly to read menus and signs, consumes more than it seems if you have not downloaded the language beforehand.

• Download Japanese for offline translation. It is what saves most in this particular destination.
• Download maps of Tokyo, Kyoto and Osaka: the Tokyo metro is enormous and looking it up on the move costs data.
• Train timetable apps (used constantly over there) consume little, but get opened many times a day.

The sums by type of use, for choosing a plan without overshooting, are in how many gigabytes you actually use on a trip.

Earthquake alerts

Japan sends early earthquake and tsunami alerts to phones, a few seconds ahead. They are loud and in Japanese, and can give a visitor a real fright. Do not switch them off: they are literally there to save lives, and those seconds are what give you time to move away from a window.