iOS · iPhone & iPad
Fix Cellular Data Not Working or Slow on iPhone
Source-checked About 10 minutes
Answer
Confirm the carrier account and coverage, turn Cellular Data on for the affected app, restart the connection, install carrier and iOS updates, then reset network settings last.
Check coverage and carrier status
Look for SOS, No Service, or a weak signal, test another location, and ask the carrier about outages, plan limits, or an inactive SIM or eSIM.
Allow cellular data
Open Settings > Cellular, turn Cellular Data on, select the intended SIM for data, and enable the affected app lower on the page.
Refresh the connection
Turn Airplane Mode on for several seconds and off, then restart the iPhone. Review Data Roaming only when your plan and location require it.
Install supported updates
Open Settings > General > About for a carrier settings prompt, then install the current iOS update.
Reset network settings last
Use Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings after saving Wi-Fi, VPN, and APN information.
Video walkthrough
If it does not work
- If cellular remains unavailable, record location, line, carrier settings, signal, plan, and time for the carrier. Do not remove an eSIM or reset network settings without recovery details.
Sources and verification
Checked against official documentation on . Scope: iPhone & iPad.
Reviewed against the linked first-party guidance; interface labels can vary by current app, service, or operating-system version.