How to avoid roaming charges (without switching your phone off)

The three ways a carrier charges you abroad

Every roaming tariff is one of three things, and knowing which one you are on tells you most of what can go wrong.

• Included. The destination is part of your plan, often up to a fair-use limit. Inside the EU, an EU SIM roams “like at home” by law, and some carriers elsewhere bundle nearby countries in. This costs nothing until you pass the limit, and past it most carriers do not say clearly what happens.
• A day pass. A fixed fee for every day you use the phone abroad, drawing on your normal allowance or a separate daily one. This is now the default for most American, British, Canadian and Australian carriers outside their home region.
• Pay as you go. A rate per megabyte, charged when no pass is active. This is where the stories of four-figure bills come from. Most carriers now either block it by default or cap the spend, but not all of them, and the cap is not always low.

The day pass, multiplied out

Day passes are sold as a small daily number, and they are reasonable for a weekend. The trouble is that nobody multiplies them by the length of the trip. The table below does that for every carrier in the English-speaking markets we hold rates for, over two weeks in each carrier's most expensive day-pass zone, which is usually “rest of the world”.

For comparison, the typical travel eSIM for a fortnight in a popular destination costs a fraction of most of those totals. The roaming cost calculator puts your own carrier next to the eSIM plans for your exact destination and trip length, which is a better answer than any average.

What counts as “using” the phone

A day pass is charged on any day the phone touches the network abroad, and the phone decides that, not you. A photo backup that resumes when you land, an app refreshing in your pocket, or one text sent over data can each start the day. Carriers also define the day differently: some by the calendar date in your home time zone, some as the twenty-four hours from first use. A late-night landing can cost two days for an hour of use.

So if you mean to use your carrier's pass only occasionally, the phone has to be set up to stay off the network the rest of the time. Which leads to the setup that avoids the question entirely.

The setup that keeps roaming at zero

1. Turn off data roaming on your home line. This one switch stops your carrier charging for data. Texts still arrive with it off, so bank codes keep working.
2. Put your data on a travel eSIM. Install it before you leave, set it as the line for mobile data, and switch on data roaming for that line only. Travel eSIMs roam onto local networks, so without roaming on they show signal and load nothing. If eSIMs are new to you, here is how they work.
3. Turn off automatic data switching. iPhones call it “Allow Cellular Data Switching”, and most Android phones have an equivalent. When the eSIM's signal dips, it quietly moves your data to the other line: your home SIM, abroad, at roaming rates. It is the most common reason people who did everything else right still get a roaming charge.
4. Decide what to do about calls. Receiving texts abroad is normally free and receiving calls usually is not. Many carriers support Wi-Fi calling abroad at domestic rates, which is the cheapest way to keep your own number for calls. Check your carrier's terms, because a few charge for it and some only support it in certain countries.

Use less, where it costs nothing to

Whichever way you pay, some data use buys you nothing on a trip. Download the maps for where you are going before you leave, so navigation works with no data at all. Set photo backup and app updates to Wi-Fi only. Download the playlists and episodes for the flight at home. None of that is about hardship, just about not paying twice for things you could have fetched on hotel Wi-Fi.

If you are unsure how much to buy, the data calculator estimates a trip from how you actually use the phone: hours of maps, video calls, streaming and hotspot. It is usually less than people expect, unless a laptop is involved.

When roaming is the right answer

Roaming is not always worse, and sometimes an eSIM is not worth the setup:

• The destination is included in your plan. An EU SIM in another EU country, or a carrier that bundles your neighbours, is already free up to its fair-use limit. Some UK carriers still include Europe after Brexit; others put it back on a daily charge. Check which kind yours is before assuming either.
• A single day. One day pass for a day trip over a border is often simpler than buying anything.
• Your phone cannot take an eSIM. An older model, or one still locked to its carrier, will not accept a travel eSIM. A local physical SIM is the alternative there, but for a short trip a day pass may be less hassle than hunting for one on arrival.

For anything longer than a few days outside an included zone, the arithmetic in the table above is hard to argue with.