eSIM Not Working on iOS 18?

Re-enable data roaming after the iOS 18 update

iOS 18 resets data roaming on eSIM lines during major updates. Go to Settings → Cellular → tap your eSIM line → Data Roaming → enable it. This is the fix for the majority of post-update eSIM failures.

Check that your eSIM line is still set as the data line

iOS 18 can reset your primary data SIM selection during update. Settings → Cellular → Cellular Data → confirm your travel eSIM is selected, not your home SIM.

Verify your eSIM profile is still installed

Very rarely, major iOS updates remove eSIM profiles. Settings → Cellular — check that all your eSIM profiles are still listed. If a profile is missing, contact your provider for a new QR code.

Reset network settings

iOS 18: Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings. This clears any corrupted network configuration introduced by the update. You will need to reconnect to Wi-Fi networks afterwards.

Toggle the eSIM line off and on

Settings → Cellular → tap your eSIM line → toggle "Turn On This Line" off, wait 15 seconds, toggle back on. This forces a fresh carrier registration with the updated iOS modem firmware.

Use Smart Coach for automatic diagnosis

Open LTE.app and tap Smart Coach. It checks your APN settings, roaming state, and carrier connection automatically — even without mobile data — and walks you through the exact fix for your device and carrier.

Did iOS 18 break eSIM?

iOS 18 resets data roaming settings during installation, which breaks eSIM connectivity for many users who had roaming enabled. The fix is simple: re-enable data roaming on your eSIM line in Settings → Cellular.

My eSIM worked on iOS 17 but broke after iOS 18. What changed?

iOS 18 changed how it stores eSIM-per-line roaming preferences during OS migration. Your hardware and eSIM profile are unchanged — only the settings were reset. Re-enable data roaming and reselect your eSIM as the active data line.

Will iOS updates always reset my eSIM settings?

Major iOS version updates (iOS 17 → 18) sometimes reset cellular preferences. Minor updates (18.0 → 18.1) generally do not. After any major iOS update, check Settings → Cellular to confirm data roaming and data SIM selection are still correct.