Land, power on, discover you can't install it. This is the single most common way an eSIM trip goes wrong, and it's entirely avoidable. The reason fits in one line: installing the profile requires an internet connection.
Downloading the profile needs a network
Scanning the QR code actually downloads a profile from the carrier's servers onto your phone. Being a download, it needs a connection — home Wi-Fi, airport Wi-Fi, or the mobile data on your existing SIM all work fine.
The trap is the loop you're in after landing: getting online needs the eSIM installed, and installing the eSIM needs you online. Airport Wi-Fi sometimes rescues you and sometimes asks for a local mobile number to send a code to — which is precisely the thing you don't have yet.
Installing and activating are separate steps
People often delay installing because they assume the clock starts the moment they do. It doesn't. The two steps are independent:
1Install — before you leave, somewhere with Wi-Fi
This downloads the profile onto your phone. All it does is add a spare line you can leave switched off. Give it a name you'll recognise, like “Japan trip”, so it's obvious in settings later.
2Activate — after you land
Turn the line on in your cellular settings, set it as the default line for mobile data, and enable data roaming for it. Only now does it start working. The exact taps are in the “After you land” section of the installation guide.
One phone, and the QR code is on it. Now what?
This is where installing early usually stalls: the QR code is in the email on your phone, and the phone that has to scan it is the same one. Two ways around it:
- 1Save the QR code from your order page as a screenshot, then choose “select from photos” on the scanning screen. Recent OS versions support this.
- 2Open the email we sent you on a laptop or tablet, put the QR code on that second screen, and scan it with your phone.
While you're at it, confirm the device
Once the profile is installed it's tied to that device, and deleting it usually means it can't be reinstalled. So before you start: the phone in your hand should be the phone you're travelling with. Every device coming with you needs its own plan.
The short version
Install it at home, on Wi-Fi, when you're not in a hurry. After landing there are only three switches left to flip. If you land and still can't get online, work through the landing-day troubleshooting order — most cases resolve in the first three steps.