How to Set Up & Activate Your Japan eSIM

Last updated: April 2026

How to set up your Japan eSIM

This takes 5 minutes. Do it at home on Wi-Fi before your trip.

Check your phone first

Your phone needs two things:

  1. eSIM support. iPhone XS or newer. Samsung S20 or newer. Pixel 3a or newer. If your phone is from 2020 or later, it almost certainly supports eSIM.
  2. Carrier unlocked. Bought directly from Apple/Samsung/Google? You’re fine. Bought through a carrier? It might be locked. Call them and ask. Unlocking is usually free.
Warning

If your phone doesn't meet both requirements, an eSIM won't work. Get a physical SIM card instead (available at Narita/Haneda airport counters or Bic Camera).

Install the eSIM

You’ll get a QR code from your provider (via email or their app). Here’s what to do with it.

iPhone

  1. Settings → Cellular → Add eSIM
  2. Tap Use QR Code
  3. Scan the code
  4. Label it "Japan Data" or whatever makes sense to you
  5. Set your original SIM for calls/SMS, the new eSIM for data

Android

  1. Settings → Network & Internet → SIMs
  2. Tap + → Download a SIM instead
  3. Scan the QR code
  4. Set the new eSIM as your mobile data line

Configure your lines correctly

This is the part people mess up. You want:

On iPhone: Settings → Cellular → configure “Default Voice Line” and “Cellular Data.”

On Android: Settings → Network & Internet → SIMs → set preferred SIM for each.

Info

If you skip this step, your phone might try to use your home SIM for data and you'll get roaming charges. Don't skip this step.

Activation

Most eSIMs activate the moment they connect to a Japanese network. Land at Narita or Haneda, your phone finds a tower, data starts flowing.

Two things that trip people up:

“Data Roaming” toggle: Many Japan eSIM providers require you to turn on Data Roaming for the eSIM line. This sounds scary but it’s fine. You’re on a prepaid eSIM. There’s nothing to “roam” into. Flip it on.

APN settings: Some providers (especially Airalo and Nomad) may require you to manually set APN (Access Point Name) settings. Check your provider’s setup guide. If your data doesn’t work after landing, this is usually the fix.

Warning

The "Data Roaming" toggle is the #1 reason Japan eSIMs don't work on arrival. If you land and have no data, check this first. On iPhone: Settings → Cellular → tap the eSIM line → Data Roaming → On.

When things go wrong

QR code won’t scan: Make sure you’re on Wi-Fi. Try entering the activation code manually (your provider should give you one). Restart your phone and try again.

No signal in Japan: Toggle airplane mode on/off. Check the eSIM line is actually enabled in your settings. Try manual network selection.

Slow speeds: Try manual network selection and pick NTT Docomo or KDDI au. If you’re underground (Tokyo Metro), speeds are limited by the station infrastructure.

Home SIM says “No Service” after installing eSIM: Your phone got confused about which line does what. Go back to cellular settings and make sure your home SIM is set as the default voice line.

Before you fly checklist

  1. Buy your eSIM (not sure which?)
  2. Install it via QR code
  3. Set eSIM as data line, home SIM for calls
  4. Turn off data roaming on your home SIM (here's why)
  5. Turn on data roaming on your eSIM line (many Japan providers need this)
  6. Screenshot the QR code. Some providers only show it once.