Guide · 2 min read ·
eSIM, SIM or Pocket Wi-Fi in Japan
Maps, train times, translation and the planner all want data. A travel eSIM is the simplest way to have it from the moment you land; pocket Wi-Fi suits a group.
In short
- A travel eSIM: bought and installed at home, on when you land. Your phone must be unlocked.
- Pocket Wi-Fi: one device for the whole group, from an airport counter or delivered to the hotel.
- Keep your home line for calls and texts, but turn its data roaming off.
- Free Wi-Fi is everywhere and often slow: don’t count on it.
eSIM, SIM or pocket Wi-Fi?
| Travel eSIM | Pocket Wi-Fi | |
|---|---|---|
| Set up | Before you fly, on the phone | At the airport, or delivered to the hotel |
| Who it serves | One phone, or its hotspot | Several phones and laptops |
| What you carry | Nothing extra | One more battery to charge |
| What it needs | An unlocked phone that takes eSIM | Nothing |
A plastic SIM is the third option. Major airports sell them, and so do electronics stores such as Bic Camera and Yodobashi Camera; the phone must be unlocked.
How to set up an eSIM before you fly
Check that your phone is unlocked and takes an eSIM.
Buy the plan and install the eSIM at home, on Wi-Fi.
Leave your home line on for calls and texts, with its data roaming off.
After landing, choose the travel eSIM for mobile data.
Important: With both lines on, the travel eSIM carries the data, but your home line can still run up roaming charges. Turn Data Roaming off for it.
On an iPhone it’s Settings → Cellular → Cellular Data to pick the line. Since iOS 26, in some countries, the phone switches back to your home SIM by itself when you’re home.
Free Wi-Fi: useful, not enough
Airports, stations, coffee chains, fast-food places and konbini have free Wi-Fi. The signal can be patchy and slow, so treat it as a bonus.
Tip: Open the planner once before you land: it keeps your days on the phone and works without a signal.
Do you need a Japanese number?
A travel eSIM usually gives data only, without a Japanese number. Your home number still takes calls and texts while its line is on.
- Messaging and call apps work over the eSIM’s data.
- Booking a restaurant or a taxi? Give your home number with its country code.
Sources
- Wi-Fi in Japan — JNTO
- Use eSIM while traveling internationally with your iPhone — Apple Support
- About cellular data roaming options for your iPhone and iPad — Apple Support
Read next
- Suica, Welcome Suica and IC Cards in Japan
- Japanese Phrases for the Trip
- Travel Insurance for Japan: What to Check
Plan your days
The planner shows these tips at each stop of your trip, offline too.
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