Keep your number, drop the roaming bill

A travel eSIM does not replace your number, it sits beside it. Your phone ends up with two lines: the one you have always had, and the one you bought for the trip. What you pay abroad comes down to a single question — which of the two is carrying your data. The setting that decides it is data roaming, and it is set line by line. Leave your usual line switched on so calls and texts still reach you, but turn its data roaming off. Turn data roaming on for the eSIM instead, and set the eSIM as the line for mobile data. From then on every app goes through the travel plan, and your carrier has nothing abroad left to bill you for. One habit is worth taking before departure: check that data roaming is off on your usual line while you are still on Wi-Fi at home. A phone that spends its first ten minutes abroad on the wrong line can cost more than the whole trip's data. The same goes for automatic updates and cloud backups — they are the ones that go looking for a network the moment you land. Calls and texts on your usual line stay billed by your carrier at its roaming rates: receiving a text is usually free, a call is not. If your bank sends login codes by SMS, that keeps working. And if data is all you need, the eSIM covers it — with whatever you do not use turned into credit rather than lost.