iPhone
Install on Wi-Fi before you fly
Open the install link or scan the QR from your order page while you still have Wi-Fi. Installing early is safe — the plan does not start until you land.
Label the line
When iOS asks, name the new line something like "Travel" so you can tell it apart from your primary SIM later.
Set it as your data line
In Settings → Cellular, set "Travel" as your Default Voice Line stays your primary number; Mobile Data goes to "Travel". Turn off "Allow Cellular Data Switching" so iOS never quietly uses your home SIM.
Turn on your travel line when you land
Toggle "Turn On This Line" for the Travel eSIM once you arrive. It connects to a local network and your data starts — that moment is when validity begins.
Disable roaming on your primary SIM
Settings → Cellular → your home line → Data Roaming: OFF. This is the single setting that prevents surprise roaming charges. The eSIM's own roaming stays ON if the plan requires it (most travel plans do).