Key takeaways
- Mobile data not working is usually caused by a switched-off setting, Airplane mode, a WiFi connection that has quietly failed, a used-up data allowance, or a temporary network problem.
- Try this order: check that mobile data is on, switch Airplane mode on for 15 seconds, then off again, turn WiFi off, restart the phone, then check the data allowance.
- If mobile data is still not working after those checks, remove the SIM, reinsert it, update the phone, then reset network settings. This clears saved WiFi passwords but keeps photos, apps and messages.
Mobile data not working is annoying, but it's rarely serious. Most of the time, it's a setting, a stuck connection, or a used-up allowance. All easy to put right. Here's how to find the cause and then fix it, starting with the easiest steps.
Why is my mobile data not working?
Mobile data is the internet connection your phone uses when it isn't on WiFi. Find what you're seeing in the table below to spot the likely cause and where to start.
| What you see | Likely cause | Where to start |
|---|---|---|
| No 4G or 5G icon at the top of the screen | Mobile data is switched off, or Airplane mode is on | Check the mobile data switch and Airplane mode |
| Full signal bars, but nothing loads | A WiFi network that is connected but not working, or a stuck connection to the network | Turn WiFi off, then switch Airplane mode on for 15 seconds and off again |
| Data worked fine, then stopped part-way through the month | The data allowance has run out | Check how much data is left on your plan |
| Data stopped after a trip abroad | The phone is still tied to a foreign network or has data roaming settings that no longer fit | Restart the phone and set network selection back to automatic |
| Data stopped after a new SIM, a new phone or a software update | The SIM isn't sitting properly, or network settings didn't reload | Reinsert the SIM, then check for carrier settings or software update |
| Other people on the same network have no data either | A network problem in your area | Check the network's status page or app, then try again later |
| Only one app won't load | The app has been blocked from using mobile data, or data saver is limiting it | Check that app's mobile data permission |
Quick fixes to try first
These six are quick to try, and a good place to start:
- Check mobile data is on. Swipe down from the top of the screen to open the quick settings (Control Centre on iPhone) and make sure the mobile data icon is switched on.
- Switch Airplane mode on for 15 seconds, then off. This makes the phone drop its connection and set up a fresh one with the network.
- Turn WiFi off. A WiFi network that is connected but not working can make it look as if mobile data has failed, because the phone prefers WiFi when it can find it.
- Restart the phone. Boring, but it works more often than it deserves to.
- Check your data allowance. If the allowance has run out, some plans stop data or slow it right down until the plan renews or you add more.
- Check for a network problem. Ask someone nearby on the same network if their data is working, or look at the network's status page or app.
Mobile data not working on iPhone
If the quick fixes didn't do it, work down this list:
- Check mobile data and the app. Go to Settings > Mobile Service > Mobile Data (on older versions, Settings > Mobile Data). Make sure it's on, then scroll down and check the app that won't load has permission to use it.
- Check data roaming if you're abroad. Go to Settings > Mobile Service > Mobile Data Options > Data Roaming.
- Look for a network settings update. Go to Settings > General > About. If an update is waiting, a prompt appears after a moment. Tap Update.
- Update iOS. Go to Settings > General > Software Update.
- Remove the SIM and reinsert it. Switch the phone off first, then use a SIM tool to open the tray. Check the SIM is sitting flat, then reinsert it.
- Reset network settings. Go to Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings. This removes saved WiFi passwords, Bluetooth pairings and VPN settings. Your photos, apps and messages stay where they are.
If you use an eSIM, the eSIM-specific steps are in our eSIM not working guide.
Mobile data not working on Android
Android menus differ between brands, so the paths below show Samsung first and Google Pixel second.
- Check mobile data. Samsung: Settings > Connections > Data usage > Mobile data. Pixel: Settings > Network & internet > SIMs > Mobile data.
- Check Data saver. It limits background data and can stop some apps loading. Samsung: Settings > Connections > Data usage > Data saver. Pixel: Settings > Network & internet > Data Saver.
- Check data roaming if you're abroad. Samsung: Settings > Connections > Mobile networks > Data roaming. Pixel: Settings > Network & internet > SIMs, then pick your SIM and check Roaming.
- Look at the access point names (APN). These are the settings that tell your phone how to connect to the network's data service. Most phones set them automatically. They're under Settings > Connections > Mobile networks > Access point names.
- Update the software. Samsung: Settings > Software update. Pixel: Settings > System > System update.
- Remove the SIM and reinsert it. Switch the phone off first, then check the SIM is seated flat in the tray.
"Could not activate mobile data network": what does it mean?
This error means the phone tried to connect to the network for data but failed. It's most often a short-lived hiccup, a settings issue, or a SIM that isn't seated properly.
Try these:
- Switch Airplane mode on for 15 seconds, then off.
- Restart the phone.
- Check for a carrier settings update or a software update. On iPhone, both are under Settings > General.
- Take the SIM out and put it back.
- Reset network settings, using the steps in the iPhone or Android sections above.
If the error keeps coming back, contact your network. They can check that your SIM is active and that the right settings are being sent to your phone.
Mobile data is on but still not working?
Mobile data can be switched on and still not work because signal bars only show the link to the nearest mast, not whether data is flowing.
4G not working, or stuck on a slow connection
A weak signal is the most likely cause when the 4G or 5G icon disappears or pages load slowly. Step outside or move next to a window, then check again.
If the signal is strong but the connection is still poor, set the network type to automatic, then restart the phone. On iPhone, go to Settings > Mobile Service > Mobile Data Options > Voice & Data. On Samsung, go to Settings > Connections > Mobile networks > Network mode.
Thinking about switching?
If the SIM test pointed to the SIM or the network, not the phone, a fresh start can be the quickest fix.
SMARTY is worth a look. It runs on Three's network, part of VodafoneThree, and covers 99.5% of the UK's outdoor population. And our plans run month to month, so there's no contract to get stuck in.
If you'd like to switch to SMARTY, you can check all SMARTY plans, or choose an eSIM if you'd rather skip the physical SIM.
FAQs
Why is my mobile data not working when I have full signal?
Full signal bars show a strong link to the nearest mast, not that data is flowing. A WiFi network that has no internet, a VPN that has lost its connection, a used-up data allowance or a temporary network problem can all block data while the bars look fine.
Will resetting network settings delete my photos or apps?
No. Resetting network settings removes saved WiFi passwords, Bluetooth pairings and VPN settings, but photos, apps and messages stay on the phone.
How do I know if my mobile data is down because of a network outage?
Ask someone nearby on the same network whether their data is working, and check the network's status page or app. If others on that network also have no data, an outage is likely. Trying the SIM in a different phone can rule out the phone.
