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Mobile data makes transport and translation easier, but the largest plan is rarely necessary. The right option depends on phone compatibility, trip length, number of devices and whether you need to share the connection.
Comparing the options
| Option | Suitable for | Advantages | Limitations |
|---|---|---|---|
| Travel eSIM | One compatible phone | Can be installed in advance; physical SIM stays in place | Often data-only; coverage and tethering depend on the plan |
| Physical SIM | Unlocked phones | Broad choice and straightforward setup | Requires swapping and safeguarding the original SIM |
| Portable WiFi | Groups or several devices | Shares one connection | Must be charged, collected and returned |
| Home-network roaming | Short trips or occasional use | Keeps the usual service | May be expensive or have a low data allowance |
Prices and packages change often. On official provider sites, compare data allowance, underlying network, fair-use policy, tethering and the exact validity period.
Before buying
Check that your phone is unlocked and eSIM-compatible if relevant. Some plans start when installed and others on first connection; follow the operator's instructions.
Save the QR code or installation details somewhere other than your email. Many codes can only be scanned once, and deleting an eSIM may require support to restore it.
Installing an eSIM
- On stable WiFi, add the eSIM through the phone settings.
- Give it a clear label such as “Japan”.
- Disable data roaming on your usual line if your tariff does not include it.
- On arrival, select the eSIM for data and enable roaming on that line only if instructed.
- Test maps and messaging before leaving the airport.
Menu names vary by iOS or Android version. Use the phone manufacturer's and provider's instructions.
Choosing a data allowance
| Main use | General guidance |
|---|---|
| Maps, messages and searches | Low consumption if content is downloaded in advance |
| Social media and photo uploads | Medium consumption, varying greatly with video |
| Video calls, streaming or work | High consumption; check limits and tethering |
Generic daily figures are unreliable. Review your own phone's usage over a typical week and add a margin. Download maps, languages, tickets and entertainment before flying.
Public and hotel WiFi
Airports, stations, hotels and some businesses provide WiFi, but coverage and quality vary. Registration may be required, and it should not be your only resource for a late arrival or night transfer.
Avoid sensitive transactions on open networks or use the protections required by your organisation. If you need a stable work connection, ask the accommodation directly; “WiFi available” does not guarantee speed or in-room coverage.
Troubleshooting
- If data does not work, check the selected line, required roaming setting and provider APN.
- If the phone has signal but no connection, restart it or toggle airplane mode.
- When tethering, monitor data use and battery level.
- Keep the physical SIM and reinstallation instructions secure.
Checklist
- ☐ Phone unlocked and compatible
- ☐ Plan and activation date checked with the official provider
- ☐ QR code and instructions stored offline
- ☐ Maps, translation and tickets downloaded
- ☐ Home-line roaming configured to prevent unwanted charges
- ☐ Emergency numbers saved: 110 for police and 119 for ambulance or fire