Data Roaming is the device-level switch that controls whether your phone uses mobile data on a visited network abroad. Turning it off blocks all background and foreground mobile data over the foreign network while leaving calls and SMS working. Turning it on lets data flow — and lets charges accumulate if your plan does not cover roaming. This guide explains exactly where to find the toggle on iPhone and Android, what the setting does and does not control, and the additional settings that prevent bill shock.
For a full explanation of how international roaming works at the network level — GSMA AA.12 agreements, IPX routing, and pricing models — see International Roaming Explained.
What Data Roaming Is and What Controlling It Does
Data Roaming is the use of mobile data on a network other than your home carrier’s network. When you travel abroad and your phone connects to a local carrier’s network, any data your device sends or receives passes through that foreign network and is billed at roaming rates — either pay-per-use, a pass fee, or consumed from an included roaming allowance, depending on your home carrier’s plan.
The Data Roaming toggle in your device settings controls mobile data on that foreign connection. When it is off:
- Your phone registers on the visited network and can make and receive voice calls and SMS normally.
- All mobile data — foreground apps, background sync, automatic updates, iCloud or Google account sync — is blocked over the visited network.
- Wi-Fi continues to work normally and is unaffected by this toggle.
When Data Roaming is on, your device behaves on the visited network roughly as it does on your home network: all apps that have permission to use mobile data will use it, including in the background.
The default state of Data Roaming depends on your device and, more specifically, on the carrier profile loaded on your SIM. Some carrier SIM profiles set Data Roaming to off by default; others set it to on. Do not assume a default — check the toggle before traveling.
If you have a SIM from an EU or EEA carrier and are traveling within the EU/EEA, you may not incur any extra roaming charge at all — the EU Roaming Regulation (Roam Like At Home) requires carriers to let customers use their domestic allowance across all 32 participating countries without surcharges (27 EU member states, Iceland, Norway, and Liechtenstein, plus Ukraine and Moldova from 1 January 2026).
How to Toggle Data Roaming on iPhone
Apple’s iOS exposes a Data Roaming toggle per SIM line, accessible in the Cellular settings.
Single-SIM iPhone
- Open Settings.
- Tap Cellular (labeled “Mobile Data” in some regions).
- Tap Cellular Data Options (or “Mobile Data Options”).
- Find the Data Roaming toggle.
- Turn it on or off as needed.
When Data Roaming is off, the toggle appears grey. When it is on, it appears green. iOS displays a confirmation dialog when you attempt to enable Data Roaming, warning that it may incur additional charges — this dialog appears as a reminder, not a permission request.
Dual-SIM iPhone (iPhone XS and Later)
On iPhone models that support dual SIM (a physical nano-SIM plus an eSIM, or two eSIMs), each line has its own Data Roaming toggle.
- Open Settings.
- Tap Cellular.
- Tap the name of the line you want to configure (for example, “Primary” or “Travel”).
- Tap Cellular Data Options.
- Adjust the Data Roaming toggle for that line.
- Repeat for the second line if needed.
If you are using a travel eSIM for data and want to keep your home SIM protected, disable Data Roaming on the home SIM line and enable it (or leave it on) for the travel eSIM line. See Using Dual SIM for Travel for the full dual-SIM configuration process.
Confirming the Setting
After adjusting the toggle, return to the main Cellular screen. Under your SIM line name, the description line will reflect whether Data Roaming is active. When you land abroad and your phone connects to the visited network, the carrier name in the status bar changes to the local operator — that is confirmation your phone has registered on the roaming network.
How to Toggle Data Roaming on Android
Android’s roaming setting is in a similar location across most devices, though the exact path varies by manufacturer and Android version.
Stock Android (Pixel and Similar)
On Android 12 and later with stock Android (Pixel devices and Android One devices):
- Open Settings.
- Tap Network & internet.
- Tap SIMs (or “Mobile network” on older Android versions).
- Select the SIM you want to configure.
- Find the Roaming toggle and enable or disable it.
On Android 11 and earlier stock builds, the path is typically Settings > Network & internet > Mobile network > Roaming.
Samsung One UI
On Samsung devices running One UI (Galaxy S and A series):
- Open Settings.
- Tap Connections.
- Tap Mobile networks.
- Find Data roaming and toggle it.
Samsung may show a confirmation dialog when you enable Data Roaming, reminding you of potential charges — behavior varies by One UI version and region.
Other Android Manufacturers
The Roaming toggle is present on all Android devices but the path varies:
- OnePlus / OxygenOS: Settings > Wi-Fi & network > SIM & network > [SIM name] > Data roaming
- Xiaomi / MIUI: Settings > SIM cards & mobile networks > [SIM name] > Data roaming
- Sony Xperia: Settings > Network & internet > Mobile network > Data roaming
- Motorola: Settings > Network & internet > Mobile network > Roaming
If you cannot locate the toggle, use the Settings search function and search for “roaming.”
Dual-SIM Android
On dual-SIM Android devices, the Roaming toggle appears separately for each installed SIM. Navigate to the SIM selection screen (typically Settings > Network & internet > SIMs) and configure each SIM independently.
Settings That Prevent Bill Shock
Turning Data Roaming off is the most direct protection, but several additional settings reduce risk when you need to use data while roaming.
Data Usage Warnings and Limits (Android)
Android provides a built-in data usage monitor with configurable warning and hard-limit thresholds:
- Go to Settings > Network & internet > Mobile network (or Data usage).
- Tap Data warning & limit.
- Enable Set data warning and enter a threshold — for example, the amount included in your roaming pass.
- Enable Set data limit to set a hard cap. When this limit is reached, Android cuts off mobile data for all apps until the counter resets or you raise the limit.
Set the warning well below your actual budget or pass limit to give yourself time to react before hitting the ceiling.
iOS does not have a built-in hard data cap, but Settings > Cellular shows cumulative data usage per line. Tap Reset Statistics at the start of each billing cycle or trip to track roaming usage from a known baseline.
Per-App Data Restrictions on iPhone
iOS lets you disable mobile data access for individual apps:
- Go to Settings > Cellular.
- Scroll down to the app list.
- Toggle off any app that should not use mobile data.
This applies to both home and roaming contexts. For travel, consider turning off apps that generate large background traffic: photo library sync, podcast auto-download, video streaming apps, and cloud backup services. For a list of high-consumption apps and their typical data rates, see the Data Usage Guide.
Data Saver and Background Data on Android
Android’s Data Saver mode (Android 7.0 and later) blocks background data for all apps except those you explicitly allow:
- Go to Settings > Network & internet > Data Saver.
- Enable Use Data Saver.
- Tap Unrestricted data to allow specific apps through the restriction.
With Data Saver on, apps can only receive data when they are actively in the foreground, preventing background sync, push notifications over data, and automatic updates from running silently. The Data-Saving Techniques guide covers additional per-app controls for high-consumption services.
Disable Automatic App Updates
Both iOS and Android can download app updates automatically over mobile data.
- iPhone: On iOS 18: Settings > Apps > App Store > turn off App Updates under Automatic Downloads. On iOS 17 and earlier: Settings > App Store > turn off App Updates under Automatic Downloads.
- Android: Google Play Store > Settings > Network preferences > Auto-update apps > select “Over Wi-Fi only.”
App updates can be large — tens or hundreds of megabytes per app — and will run in the background without prompting you.
Roaming Control in Dual-SIM Devices
Dual-SIM devices introduce a configuration that is increasingly common for travelers: running a home SIM alongside a travel eSIM or local SIM. In this setup, roaming control becomes per-line rather than per-device.
The Standard Travel Dual-SIM Configuration
The most common and cost-effective dual-SIM travel setup:
- Home SIM: Data Roaming off. Voice calls and SMS continue to work on your home number. No mobile data runs on this line, so your home carrier does not see any roaming data usage.
- Travel eSIM (or local SIM): Data Roaming on (or simply set as the primary data SIM). All data traffic runs on the travel SIM at local or regional rates.
Your home number remains reachable for calls and messages without any roaming data cost. When a caller dials your home number, the call still routes through the visited network’s voice path — but voice is not controlled by the Data Roaming toggle.
Line Assignment for Data
On both iPhone and Android, you designate which SIM handles mobile data:
- iPhone: Settings > Cellular > Cellular Data — select the SIM to use for data. This is typically the travel SIM when traveling.
- Android: Settings > Network & internet > SIMs > Mobile data — select the SIM.
Setting the travel SIM as the data SIM means Data Roaming is not engaged on the home line even if it is technically turned on — the home SIM is not being asked to provide data. However, explicitly turning Data Roaming off on the home SIM provides an additional safeguard against any background data switching.
For the complete step-by-step setup, including SMS two-factor authentication considerations and returning to home-only configuration, see Using Dual SIM for Travel.
The Difference Between Data Roaming, SMS Roaming, and Voice Roaming
Data Roaming is one of three types of roaming service:
| Type | Controlled by Data Roaming toggle | Notes |
|---|---|---|
| Data roaming | Yes | Mobile internet access on the visited network |
| SMS roaming | No | Text messages work independently of the Data Roaming toggle |
| Voice roaming | No | Calls work independently of the Data Roaming toggle |
When you turn Data Roaming off, your phone does not go silent. Incoming and outgoing voice calls and SMS continue to function through the visited network’s circuit-switched and SMS paths, which are separate from the data infrastructure.
If you want to block voice and SMS roaming charges as well, you must either:
- Enable Airplane Mode (blocks all radio), then re-enable Wi-Fi manually, or
- Contact your home carrier to restrict international voice and SMS at the account level.
Some carriers offer account-level controls through their apps or web portals that restrict roaming usage by service type. Check your carrier’s app for these options before traveling.
Resetting After Returning Home
When you return to your home country, your phone reconnects to your home carrier’s network automatically. A few settings are worth confirming to restore normal operation:
1. Verify Data Roaming state. Whether you want it on or off at home is a personal preference, but confirm it is in the state you expect. Some carrier SIM profiles toggle it back automatically; most do not.
2. Reassign the data SIM (dual-SIM devices). If you switched mobile data to a travel eSIM while abroad, switch it back to your home SIM. The travel SIM may no longer have active data once its plan expires or the destination-limited plan becomes inactive.
3. Re-enable automatic app updates and background data. If you disabled these to save roaming data, re-enable them after returning to your home network.
4. Reset the data usage counter. On iPhone (Settings > Cellular > Reset Statistics), reset the counter at the start of each billing cycle. This gives you an accurate view of next month’s usage separate from any roaming consumption.
5. Check your carrier app for usage charges. Review your account before the billing period closes to catch any unexpected roaming charges while there is still time to raise a query with your carrier.
What to Check Before Your Next Trip
A brief pre-departure checklist for data roaming settings:
- Confirm your plan’s roaming coverage — verify your destination is covered and which pricing model applies (pay-per-use, day pass, or included).
- Decide your data strategy — home SIM roaming, travel eSIM, or local SIM. This determines which lines should have Data Roaming on or off.
- Set Data Roaming to the correct state on each SIM line.
- Configure data usage warnings — set a threshold on Android, or note the current Usage counter baseline on iPhone.
- Disable automatic app updates over mobile data.
- Turn off apps you do not need abroad using per-app controls.
- Install a travel eSIM before departure if using one — eSIM profile downloads require an internet connection, ideally done over Wi-Fi at home.
For a comprehensive list of settings to verify before any international trip, see the Pre-Trip Connectivity Checklist.
FAQ
See the FAQ items above for answers to:
- Where to find Data Roaming on iPhone
- Where to find Data Roaming on Android (including Samsung One UI and Pixel)
- What happens when Data Roaming is off
- Whether turning Data Roaming off affects calls and SMS
- How to set a data warning or cap
- How to restrict individual apps from using roaming data
- How to configure Data Roaming on dual-SIM devices
Related Guides
- International Roaming Explained — How GSMA AA.12 agreements and IPX routing keep your home SIM working abroad
- EU Roaming Explained — Roam Like At Home regulation: 32 countries covered (27 EU + EEA + Ukraine/Moldova from 2026) and who benefits
- How Much Mobile Data Do You Need? — Per-app data consumption estimates to plan your roaming budget
- Using Dual SIM for Travel — Keep your home number while routing data through a travel eSIM
- Data-Saving Techniques — iOS and Android settings that cut mobile data use