The moment a plan's validity starts: on purchase, on install, on first use or on arrival.
Two plans with the same number of days can behave differently. One starts counting as soon as you install it at home. Another waits until the eSIM first connects to a network in a covered country.
The difference matters most when you install before the flight, which is the recommended way to set up.
What to check
- Read the activation line on the plan page
- If days start on install, install close to the departure date