别让漫游账单吓一跳：出发前该关掉哪些设置
意外的漫游费用来自少数几个设置，出发之前全都可以关掉。
快速解答
- Turning off home-SIM data roaming and disabling automatic data switching closes almost every path to a surprise bill.
- Re-check after an operating system update: updates sometimes reset these switches.
| Item | Why it happens |
|---|---|
| Switch | What turning it off stops | What keeps working |
|---|---|---|
- 1
- 2
- 3
- 4
- 5
- 6
常见问题
If data roaming is off, do I still need to turn mobile data off?+
If you have bought a travel plan, do not turn mobile data off, because that disables the plan as well. Turn roaming off on the home line and leave mobile data on so the travel line can work. If you bought no plan at all and intend to live on Wi-Fi for the trip, then switching mobile data off for the whole device is the most straightforward approach.
Is airplane mode on its own enough?+
It is enough while it is on, in that no radio is active. But it is not a configuration, because you will switch it off the moment you want to use the travel plan — and if the home line still has roaming enabled at that point, everything comes back at once. Airplane mode is the right temporary measure in the air or near a border; the per-line settings are what actually protect you for the whole trip.
Can I still be charged for roaming after buying a travel eSIM?+
Yes, if the home line is still in the phone with roaming enabled. A travel eSIM is an additional line; it does not switch off the existing one for you. Both can be live at the same time, and background activity may pick the old one without your noticing. Buying the plan and closing the old line are two separate jobs, and both need doing.
Is there a charge for answering a call while abroad?+
Answering a call abroad is normally chargeable, and in many arrangements a missed call that lands in voicemail is too. The rates and conditions are set by that number's operator and differ by destination, so we cannot quote a figure on their behalf. Ask them before you travel — or, if you do not need to take calls at all, disabling the line is the unambiguous answer.
Travelling through several countries — do I reconfigure at every border?+
The configuration that keeps the home line closed stays in place for the whole trip; there is nothing to redo. What is worth checking at each crossing is whether the travel line still works in the new country, which depends on the countries that plan covers. Read the plan's own details — and if it does not cover the next country, do not re-enable roaming on the old line as a quick fix.
常见问题
With roaming off, will SMS codes still arrive?+
Usually yes, since SMS does not use data, but receiving it abroad still depends on your home operator's terms, so check before you travel.
Is leaving airplane mode on safer?+
It removes the risk but also removes calls and SMS entirely. The balanced route is home-SIM data off with the eSIM carrying the internet.