eSIM, pocket Wi-Fi or SIM card: getting data in Japan
Which data option suits your trip, how to install a Japan eSIM step by step, how much data you need, fixes when it will not connect, and whether you need a Japanese phone number.
You will use data constantly in Japan: train routes, maps, translation, restaurant bookings, QR tickets and digital passes. Free public Wi-Fi exists in airports, many stations and convenience stores, but it is patchy and often needs a sign-in. Sort out data before you land and arrival day becomes much easier.
Most visitors with a recent unlocked phone should buy a data-only eSIM before they fly.
- eSIM: best for solo travellers and couples. Install at home, switch on when you land.
- Pocket Wi-Fi: best for families and groups sharing one connection, or for locked phones.
- Physical SIM: for unlocked phones without eSIM support.
- How much data: heavy map and social media users get through about 1–2 GB a day.
The three options compared
| eSIM | Pocket Wi-Fi | Physical SIM | |
|---|---|---|---|
| Best for | Solo travellers and couples with new phones | Families and groups sharing one plan | Older unlocked phones without eSIM |
| Set up | Install at home, switch on at landing | Collect at the airport or hotel | Buy at the airport or electronics stores |
| Devices | One phone (hotspot often allowed) | Several devices at once | One phone |
| Downsides | Phone must be unlocked and eSIM-compatible | Must be charged and carried; return it at the end | Easy to lose your home SIM in the swap |
| Phone number | Usually data only | No | Usually data only |
Before you buy: check your phone
- Is it unlocked? A phone locked to your home carrier will not accept another carrier's eSIM or SIM. Check in your phone settings or ask your carrier. On iPhone, Settings → General → About shows "No SIM restrictions" when it is unlocked.
- Does it support eSIM? iPhone XS and later, and most recent Pixel and Galaxy phones, do. Some models sold in mainland China and Hong Kong do not.
- Compare with your home roaming plan. Some carriers include Japan roaming or sell a daily travel pass. That can be simpler, though usually dearer than a travel eSIM.
How to set up an eSIM, step by step
- Buy a Japan plan sized to your trip. Data-only plans by days and gigabytes are the norm; unlimited plans often slow down after a daily allowance.
- Install it at home on Wi-Fi a day or two before you fly, by scanning the QR code or using the provider's app. Most plans do not start counting days until the eSIM first connects in Japan, but check yours.
- Label the line ("Japan data") so you can tell it apart from your home line.
- Do not delete it. Many eSIMs can only be installed once.
- On landing, switch the eSIM line on, set it as the line for mobile data, and turn on data roaming for that line only.
- Keep your home SIM on for calls and texts if you need bank security codes, but turn off its data roaming to avoid charges.
How much data do you need?
| How you use your phone | Per day (rough guide) |
|---|---|
| Maps, train routes, messaging, a little browsing | 0.5–1 GB |
| Plus social media, photo uploads, translation apps | 1–2 GB |
| Plus video calls, streaming or hotspotting a laptop | 3 GB or more |
Hotel Wi-Fi covers most evenings, so few visitors need truly unlimited data. If you are unsure, buy a mid-sized plan; most providers let you top up from the app.
Worked example: a family of three for 10 days
Estimate Usage only; plan prices vary by provider and change often, so compare current prices before buying.
| Option | What you would buy | Trade-off |
|---|---|---|
| Three eSIMs | Two adults at about 1–2 GB a day (10–20 GB each) and a smaller plan for the third traveller | Everyone independent; three plans to pay for and install |
| One pocket Wi-Fi | One unlimited router for 10 days | One price; everyone must stay near the router and it needs charging |
| One eSIM plus hotspot | One large plan (30 GB+) on one adult's phone, shared by hotspot | Cheapest; drains that phone's battery fast |
Families who move around together often find one router or one big hotspot plan easiest; families who split up for the day usually want one eSIM per adult.
Do I need a Japanese phone number?
Rarely. Some restaurant bookings, taxi apps and lotteries ask for one, but most apps visitors use work with your home number or email. Some providers sell plans with a Japanese number if you need one. Keep your home number active for bank and booking verification codes, especially if you plan to book the shinkansen online.
Battery and power banks
Navigation and QR tickets drain batteries fast. Carry a power bank. Airlines limit power bank sizes and many now ban using or charging them in flight. Keep them in your carry-on, never in checked luggage, and do not put them in a suitcase you send ahead by courier.
Pocket Wi-Fi: pickup, battery and return
- Pickup: most rental companies let you collect at an airport counter, a post office counter or your hotel. Book online a few days ahead and bring the confirmation.
- Battery: a router typically lasts most of a day. Charge it every night and carry a power bank.
- Return: usually in a prepaid envelope dropped into a post box or at an airport return box. Lost or late routers are charged, so keep the envelope safe.
- Range: everyone needs to stay near the router. If your group splits up for the day, one person keeps the internet.
Physical SIM cards
Tourist data SIMs are sold at airport counters, large electronics stores and some vending machines. They suit unlocked phones without eSIM support.
- Keep your home SIM in a labelled bag or the SIM tray card so you do not lose it.
- Bring a SIM tool or a paperclip.
- Check the plan's data allowance and validity before paying; plans are sold by days and gigabytes like eSIMs.
Free Wi-Fi as a backup
Airports, many major stations, convenience stores and most hotels offer free Wi-Fi, though some networks need a short sign-up or an email address. It is fine for checking a route or messages, but too patchy to rely on for maps while you walk. JNTO lists free Wi-Fi options for visitors on its official site.
Common mistakes
- Deleting the eSIM after installing it, or while troubleshooting. You may not be able to reinstall it.
- Leaving home-SIM data roaming on. Your phone may quietly use the expensive line.
- Buying for a locked phone. It will not work. Get a pocket Wi-Fi instead.
- Waiting until you land to install. You need a connection to install, and airport Wi-Fi in the immigration queue is unreliable.
FAQ
Is an eSIM or pocket Wi-Fi better for Japan?
An eSIM is easier for one or two people with recent unlocked phones. A pocket Wi-Fi suits families and groups who stay together, or anyone whose phone is carrier-locked.
How much data do I need per day in Japan?
About 0.5–1 GB a day for maps, transit and messaging, and 1–2 GB a day with social media and photo uploads. Video calls and streaming need more.
When should I install my Japan eSIM?
At home on Wi-Fi a day or two before you fly. Then switch it on and turn on its data roaming when you land.
Do Japan eSIMs come with a phone number?
Usually not. Most travel eSIMs are data-only. Keep your home number active for calls and security codes.
Will my phone work in Japan?
Most recent phones work on Japanese networks. To use a Japan eSIM or SIM the phone must be unlocked and support the plan you buy.
