Staying Connected Abroad: Roaming, eSIMs and Avoiding Large Bills

Mobile data abroad is one of the few travel costs that can become large without you doing anything. It is also one of the easiest to control, once you know which option suits your trip.

The options

• Your existing plan's roaming. Simplest. Some plans include roaming in certain regions; others charge daily or per megabyte. The per-megabyte rates outside included regions are where the alarming bills come from.
• A local physical SIM bought at the destination. Often the cheapest for a longer stay, and requires an unlocked phone and some time on arrival.
• An eSIM — a data plan downloaded to the phone before you travel. Convenient, increasingly the default for short trips, and requires a phone that supports eSIM.
• Portable hotspot device. Useful for groups or for several devices, and one more thing to charge and carry.
• Wi-Fi only. Free, and unreliable when you need directions.

Comparing eSIM plans honestly

• Coverage area. A regional plan is only useful if it covers every country on your route.
• Which local network it uses, since coverage differs considerably outside cities.
• Data allowance and validity period together — a large allowance over a short window may not suit.
• Whether it includes a phone number. Many eSIM plans are data only, which means no calls or texts to that number. This matters if you rely on text codes for banking.
• Whether tethering is allowed, if you need to connect a laptop.
• What happens when data runs out — top-up or dead.

Check your phone supports eSIM and is not carrier-locked before buying one.

Settings that stop surprise charges

1. Turn off data roaming until you have set up whichever option you chose.
2. Set a data warning and limit in the phone's settings.
3. Turn off automatic app updates on mobile data.
4. Turn off background app refresh for anything you do not need live.
5. Download maps, tickets and documents offline before leaving.
6. Check which line is used for data if you are running two SIMs, since it is easy to leave the home line active.

The last one causes most of the bills people get after using an eSIM correctly.

Calls and messages

Voice calls are frequently charged separately from data even on plans that include roaming, and receiving calls abroad can also be charged. Where you can, use data-based calling instead. Keep the home number reachable if you need it for verification codes — that is a reason to keep the original SIM active rather than removing it.

Practical extras

Two-factor authentication tied to a number you cannot receive abroad is a common and stressful problem. Set up an authenticator app or backup codes before travelling, not while standing in an airport.

Before you order

Check your phone is unlocked and eSIM capable. Check the plan covers every country on your route and states which network it uses. Check whether it includes a number or is data only. And check your own operator's roaming terms first, since it may already be included and cost nothing.