Short Answer: Install 1-2 days before your trip while you have stable WiFi.
⏱️ The Best Timeline
| When | What to Do |
|---|---|
| 1-4 weeks before | Purchase your eSIM. QR code arrives instantly via email. |
| 1-2 days before | Install the eSIM at home/office with good WiFi. |
| At the airport | Double-check settings: Data Roaming ON, correct line selected. |
| Upon landing | Turn off Airplane Mode. Connect automatically! |
❓ Why not wait until the airport?
- Airport WiFi is unreliable – Long queues, weak signals, login walls.
- Stress-free arrival – Land, connect, navigate immediately.
- No countdown – Most Roamiya plans only start when you connect abroad.
🔄 What if I install now?
Installing early does NOT start your plan. The validity timer only begins when:
- The eSIM is installed, AND
- Your phone connects to a local network at your destination.
So installing at home in London won't use up your Japan data!