How to stop app updates and backups eating your travel eSIM data

What uses travel data without you noticing?

The usual list is short, and every item can be large:

Which switches should I change, in what order?

1. Update everything on Wi-Fi before you leave. Install pending system updates and app updates at home, and open big apps once so they finish downloading content.
2. Stop app store downloads on mobile data. iPhone: Settings, App Store, turn off Automatic Downloads under Cellular Data. Android: Play Store, Settings, Network preferences, Wi-Fi only.
3. Set the travel line to Standard or Low Data Mode. On iPhone 5G models avoid Allow More Data on 5G, which Apple says permits iOS updates over cellular and automatic iCloud backups.
4. Limit Background App Refresh. iPhone: Settings, General, Background App Refresh, set to Wi-Fi only or off. Android: restrict background data for heavy apps.
5. Keep photo backup on Wi-Fi. Turn off cellular data for iCloud Photos or Google Photos backup during the trip.
6. Stop chat apps auto-downloading media. In WhatsApp, Settings, Storage and data, set media auto-download on mobile data to nothing.
7. Check the per-app list after day one. Look for system services, backups and app stores near the top and switch off whatever you missed.

Where are the iPhone settings?

• Data Mode for the travel line: Settings → Cellular → the travel line → Data Mode. Choose Standard or Low Data Mode. Apple says Allow More Data on 5G enables iOS updates over cellular, automatic iCloud backups and higher-quality video. It notes this mode uses more cellular data.
• App Store: Settings → App Store. Under Cellular Data, turn off Automatic Downloads. Set App Downloads to Ask If Over 200 MB or Always Ask, and turn video autoplay off.
• Background App Refresh: Settings → General → Background App Refresh. Choose Wi-Fi or Off, or switch it off for individual apps.
• Per-app cellular access: on the Settings → Cellular list, any app can be switched off so it only uses Wi-Fi.
• System Services: at the bottom of the Cellular list, tap System Services to see what the system itself used.

Where are the Android settings?

Paths vary by maker. These are for Pixel, with the Samsung names where they differ:

• Play Store updates: Play Store → profile picture → Settings → Network preferences. Set Auto-update apps and App download preference to Wi-Fi only.
• Data Saver: Pixel: Settings → Network & internet → Data Saver. Samsung: Settings → Connections → Data usage → Data saver. Data Saver limits background data for most apps.
• Background data per app: long-press an app → App info → Mobile data & Wi-Fi, then turn off background data.
• Data warning: Pixel: Settings → Network & internet → SIMs → Data warning & limit. Google says the phone notifies you when usage reaches the number you set.

How do I keep photo backup off the travel line?

Photo backup is the single biggest silent user for many travellers, because video files are large. On iPhone, open the Photos settings (Settings → Photos, or Settings → Apps → Photos on recent iOS) and turn off Cellular Data. In Google Photos, open the backup settings and turn off backup over mobile data. Your photos stay on the phone and upload on the next Wi-Fi. See photo backup and upload data for sizing.

What about WhatsApp and other chat apps?

In WhatsApp, open Settings → Storage and data. Under media auto-download, set "When using mobile data" to no media, or photos only. You can still tap any video to download it. The same section has an option to use less data for calls. Chat backups should also be set to Wi-Fi only.

How do I check that it worked?

On the first evening, open the per-app list for the travel line. On iPhone, Settings → Cellular, with the statistics reset before you left. On Pixel, Settings → Network & internet → SIMs → App data usage. If System Services, Photos, App Store or a cloud app is near the top, the switch for that item is still on. Our iPhone and Android tracking guides go further.

What about laptops, tablets and other devices?

Every device on your hotspot brings its own updates and backups. A tablet that hasn't been opened for a month may start a large system update the moment it connects. A laptop may start syncing a cloud folder. Before the trip, update and sync every device you are taking, on home Wi-Fi. On the trip, mark the phone's hotspot as a metered or low-data network on each device. Windows has Metered connection for a Wi-Fi network, and recent macOS versions have Low Data Mode per Wi-Fi network. Our laptop hotspot guide lists both.

Do email and attachments matter?

Text email is small. Attachments are not, and some mail apps download attachments automatically. If your mail app has an option to load attachments or remote images only on Wi-Fi, use it for the trip. Large files you need for work are better downloaded on hotel Wi-Fi the evening before.

How much can these switches save?

It depends on what would have run. On a trip with no pending updates and backup already off, very little. On a phone with a waiting system update, a game patch and a week of photos and videos queued for backup, it can be several GB. That is often more than the rest of the trip's browsing and maps together. The cheapest moment to find out is the first evening: one look at the per-app list tells you.