What is data roaming, and should you have it on or off?

What is data roaming?

The answer to "what is data roaming" is simple: it is your phone using mobile data on a network that isn't your own carrier's. It happens almost entirely abroad: your US carrier has no masts in France, so your phone borrows a French network, and the French network bills your carrier, which bills you.

Google's Pixel help describes the roaming setting in one line: it lets your phone send data over other carriers' networks when you leave an area your carrier covers. That is the whole mechanism. The switch in your settings decides whether your phone is allowed to do it.

This guide is general explanation plus figures and settings paths from AT&T, Verizon, Apple and Google, read on 9 November 2026.

What does roaming mean on a phone?

Roaming means your phone is connected to any network other than your home carrier's. It covers calls and texts as well as data, which is why you may see "roaming" next to the signal bars even with data roaming switched off.

There are two kinds. International roaming is the one that costs money: you are in another country on a foreign network. Domestic roaming happens when your carrier hands you to a partner network inside your own country, often in rural areas. Domestic roaming is often included in US plans, so the data roaming switch matters mainly when you travel, but your plan's terms are the place to check.

"Data roaming" is the narrower term. It means mobile data over a foreign network, and it has its own switch because data is where roaming bills get large. A phone checking email, syncing photos and refreshing apps in the background can use a lot without you touching it.

What are roaming charges?

Roaming charges are what your carrier bills you for using a foreign network. Without a pass or plan, they are pay-per-use, and the rates are high. AT&T's pay-per-use page lists, for most countries:

At $2.05 per MB, a single gigabyte would cost over $2,000. That is why carriers sell daily passes instead. AT&T's International Day Pass is $12 a day, and Verizon's TravelPass is $12 a day in most countries and $6 a day in Mexico and Canada. Over a ten-day trip outside Mexico and Canada, either pass comes to $120 for one line, before taxes and fees.

One detail matters for the switch. AT&T says the Day Pass charge starts the first time you use data, send a text, or make or accept a call in an included destination. Verizon says a TravelPass session starts automatically when you use your device in a TravelPass country. So with roaming left on, an app syncing in the background can start a day's charge without you noticing.

Should data roaming be on or off?

It depends on which line you mean and what you have paid for.

• Home line, no travel plan bought: off. This is the line that would run up pay-per-use charges or trigger a daily pass.
• Home line, carrier pass bought on purpose: on. The pass only works if the phone can roam. Apple says that if you have an international data plan, you may need data roaming on.
• Travel eSIM line: usually on. Travel eSIMs connect through partner networks, so your phone often counts their data as roaming. Airalo's iPhone guide tells you to set Data Roaming on or off as the Airalo app instructs, and to accept the pop-up if it asks you to enable roaming for the eSIM.
• At home in the US: leaving it on is usually harmless where your plan includes domestic roaming, but check your plan.

So the common answer for someone travelling with an eSIM is both: data roaming on for the travel eSIM, off for the home line. On a dual SIM phone, the setting is per line, which makes that possible.

If you see "data roaming is turned off" in a message or notification, it means exactly that: your phone found a foreign network but isn't allowed to use its data. Turn it on only for the line you intend to pay for.

How do you turn data roaming on or off on iPhone?

Apple's steps for a phone with one SIM or eSIM:

1. Open Settings and tap Cellular (Mobile Data in some regions).
2. Make sure Cellular Data is on.
3. Tap Cellular Data Options.
4. Turn Data Roaming on or off.

On an iPhone with two lines, Apple says to tap the number you want to change first, then Cellular Data Options, then Data Roaming. Do this once for your home line and once for your travel eSIM. Apple also suggests turning on any other settings your carrier recommends.

If your iPhone shows No Service or SOS only abroad, Apple's first check is that Data Roaming is on for the line you are using.

How do you turn roaming on or off on Android?

Google's Pixel help puts it under Settings, then Network & internet, then SIMs, where Roaming appears among the options for each SIM. Google notes that options vary by phone and Android version, so a Samsung or other Android phone may use different labels. Look in the network or connections section of Settings for the SIM or mobile network entry, then the roaming switch.

As on iPhone, the setting is per SIM on a dual SIM phone. Pick the travel eSIM's line and turn roaming on there; pick the home line and leave it off.

How do you avoid roaming charges altogether?

Three ways, from cheapest to simplest:

1. Wi-Fi only. Keep data roaming off on every line and use Wi-Fi. Free, if you can live without maps on the street.
2. A travel eSIM. Install a prepaid data plan before you leave, set it as your data line, and keep data roaming off on your home line. Prices from Airalo, Nomad, Saily and Holafly are on the cheapest eSIM page, sorted by cost per gigabyte. Check the phone first on our eSIM compatible phones list.
3. Your carrier's pass. The simplest, as your number and plan carry on unchanged, and usually the most expensive per day.

Inside the EU, people with an EU plan get roam-like-at-home rules, so the calculation is different. This guide is written for US phones travelling abroad.

What is cellular roaming on a prepaid plan?

The same thing, with a different bill. Cellular roaming works the same way on prepaid and postpaid lines; what changes is whether your plan allows it and how it is charged. A prepaid plan may not include international roaming at all, or may sell it separately. Check your carrier's international page before you leave rather than finding out at the airport.