Verified against Ofcom Connected Nations Spring 2026, Opensignal April 2026 reports and current operator tariffs.
Quick answer — start here: 1) Toggle Aeroplane Mode on / off. 2) Confirm Mobile Data is enabled and Data Roaming matches your contract. 3) Restart the phone. If still broken, the fixes below cover 95% of UK cases on EE, O2, Three, Vodafone, VM O2, Voxi, giffgaff and other MVNOs.
9 fixes for “mobile data not working” — in priority order
Aeroplane mode toggle
Swipe down, tap aeroplane icon on, wait 10 sec, tap off. Forces a fresh registration to the nearest mast — fixes ~30% of “no data” cases instantly.
Confirm mobile data is on
iPhone: Settings → Mobile Data → toggle on. Android: Settings → Network → Mobile Network → Mobile Data on. Look for the 4G / 5G icon in your status bar.
Restart the phone
Full power-off, wait 30 sec, power on. Clears stuck radio firmware. Boring, but fixes another 25% of cases.
Re-seat or swap the SIM
Eject the SIM tray, gently wipe the gold contacts, refit. If a friend’s phone shows the same problem with your SIM, the SIM is dead — request a free replacement from your network.
Check APN settings
The #1 cause after a SIM swap. Each network has specific APN values. See our APN settings UK guide for the exact values for EE, O2, Three, Vodafone, Voxi, giffgaff, Smarty and more.
Force network mode
Settings → Mobile Network → Preferred Network Type → set to “5G/4G/3G Auto” or “4G Preferred”. If you are stuck on a single mode in poor coverage, switching to Auto is often the fix.
Reset network settings
iPhone: Settings → General → Transfer / Reset → Reset → Reset Network Settings. Android: Settings → System → Reset → Reset Network. Wipes Wi-Fi passwords too — keep them handy.
Check your bill / spend cap
If you have hit a data limit or spend cap, the network suspends data. Log into the network app and check usage. See what is a spend cap for how to lift it.
Check the network’s status page
Real outages do happen. Bookmark O2 service status, EE, Vodafone and Three status pages — confirm before you spend an hour debugging your phone.
Network-specific quirks (UK 2026)
| Network | Common fix you should try first |
|---|---|
| EE | APN everywhere, MMS APN everywhere — both required. After ports, EE often needs a 24-hour cycle before data fully provisions. |
| O2 & VM O2 | APN mobile.o2.co.uk, username o2bb, password password. New SIMs sometimes ship with data disabled — call 202 to enable. |
| Three | APN 3internet. 5G-only mode causes drop-outs in mixed-coverage areas; force 4G/5G Auto. |
| Vodafone | APN internet, username web, password web. Data Roaming must be ON for some EU SIM variants. |
| Voxi | APN pp.vodafone.co.uk. The free-social allowance can mask “no data” — try a non-social site to test. |
| giffgaff | APN giffgaff.com, username giffgaff. New SIMs need activation via the giffgaff app first. |
Repeated mobile data issues across your team?
If multiple SIMs keep dropping data, the problem is usually the network or contract — not your phones. We diagnose for free and switch you to a better fit.
iPhone-specific fixes
- Carrier settings update. Settings → General → About — if a carrier update is available, a popup appears within 15 seconds. Always install.
- Reset eSIM. Settings → Mobile Data → tap your eSIM → Delete eSIM, then re-add via QR code from your network.
- Disable Low Data Mode. Settings → Mobile Data → Mobile Data Options → Low Data Mode = OFF. It can throttle background apps to apparent “no data”.
- 5G Standalone toggle. Settings → Mobile Data → Voice & Data → set to “5G Auto” not “5G On” if you’re losing data in fringe coverage.
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Android-specific fixes
- Clear “Mobile Network” cache. Settings → Apps → Show System → Mobile Network → Storage → Clear Cache. Often resolves stuck connection state.
- Check VPN. A misconfigured VPN routes traffic to a dead endpoint. Disconnect any VPN, retry data, then reconnect.
- Update carrier services. Open Play Store → search “Carrier Services” → Update. Critical for VoLTE, VoWiFi and some MVNO data.
- Power-off + remove SIM. Some Samsung models need the SIM fully removed during a power cycle to re-init the radio firmware.
Still no mobile data — when to escalate
If you have tried every step above and still have no data on a single SIM — call your network. Most likely a provisioning fault or a corrupted SIM, both fixable in under 10 minutes by support.
If multiple SIMs across your team are losing data on the same network — it is the network, not you. Check the network’s published status page, and if confirmed an outage, your usual SLA applies. Long term, a multi-network strategy avoids single-supplier risk.
Frequently asked questions
FAQs about mobile data not working
Persistent data problems on a consumer plan? Most UK SMEs save 20–35% on data by moving to a proper business contract — see our pick of the best business mobile phone plans.
pp.vodafone.co.uk. Check your free-social allowance hasn’t masked the issue — load a non-social website to test real data. If still no data, restart the phone and toggle aeroplane mode.Related Reading
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