How to install an eSIM on iPhone

Installing an eSIM on an iPhone takes about two minutes. The only real decision is when to do it — and the answer is almost always "at home, before you fly".

Install before you fly (seriously)

Your eSIM is delivered instantly by email after checkout, but installation needs an internet connection. Do it on your home WiFi, at your own pace, while a working phone is still in your hand. Nothing about installing activates most plans early — the clock typically starts when the eSIM first connects to a network at your destination.

Step-by-step: adding the eSIM

1. Open Settings → Mobile (called Cellular on some regions' iPhones).
2. Tap Add eSIM.
3. Choose Use QR Code and scan the QR code from your Onda email — or, if you're reading the email on the same phone, just tap the one-click install link and iOS handles the rest.
4. Follow the prompts. Label the new line something obvious like "Onda Japan" so it's easy to find later.
5. When asked which line to use for mobile data, you can leave your home SIM selected for now — you'll switch when you land.

That's it. The eSIM now sits on your phone, dormant, costing nothing.

When you land: three switches

1. Settings → Mobile → your Onda eSIM → turn the line On.
2. On the same screen, set Mobile Data to the Onda eSIM.
3. Turn Data Roaming ON for the Onda line.

Wait — roaming ON? Doesn't that cost a fortune?

This is the step that trips people up, and it's completely safe. Travel eSIMs are technically "roaming" onto local partner networks — that's just how they work under the hood. The roaming toggle only enables the connection; it doesn't add charges. Your plan's price is your plan's price. The expensive kind of roaming is your home SIM roaming — which is exactly why you leave data roaming OFF on your home line.

Troubleshooting

No signal after landing? Give it a few minutes — first-time network registration can be slow. Then toggle Airplane Mode on and off. Still nothing? Restart the phone. This fixes the vast majority of cases.

Connected but no data? Check that Mobile Data is set to the eSIM line and Data Roaming is on for it. If your plan's instructions mention an APN setting, enter it under Settings → Mobile → your eSIM → Mobile Data Network.

Can't scan the QR code? You can't scan a QR displayed on the same phone you're installing to — open the email on a laptop or another screen, or use the one-click link instead.

Anything else, our help page has you covered.

Keep your home number alive

Leave your home SIM installed and turned on, with data roaming off. You'll still receive the SMS codes your bank insists on sending, and WhatsApp keeps working on your existing number — it's tied to your account, not your SIM. Data flows through the eSIM; your number stays yours.

Ready to go?

Grab a plan for Japan, Bali, Thailand, Europe, New Zealand or wherever you're headed, install it tonight, and land connected. On Android? Here's the Android version of this guide.