Fix LTE/4G Not Working on iPhone: Step-by-Step

If your iPhone shows “No Service” or keeps dropping to 3G, the fix usually involves a quick settings reset, a carrier update, or a SIM card reseat. This guide walks you through the most effective troubleshooting steps, from the simplest toggles to more advanced network resets, so you can get your LTE or 4G connection back.

Why Your iPhone Loses LTE/4G

LTE (Long-Term Evolution) is the standard for high-speed mobile data, and when it stops working, the cause is often one of a few common issues. These include temporary network outages, incorrect network settings, a glitched carrier configuration, a damaged or dislodged SIM card, or even a software bug in iOS. Rarely is it a hardware failure, so most issues can be resolved by the user without a trip to the Apple Store or carrier.

Quick Fixes to Try First

Start with these zero-risk steps—they resolve a surprising number of LTE issues and take less than a minute each.

Toggle Airplane Mode: Swipe into Control Center, tap the airplane icon, wait 10 seconds, and tap it off. This forces your iPhone to re-register with the nearest cell tower.
Restart Your iPhone: Press and hold the side button and either volume button until the power slider appears, then slide to power off. Wait 30 seconds, then turn it back on. This clears temporary software glitches.
Check for Carrier Settings Update: Go to Settings > General > About. If an update is available, a pop-up will appear. Tap “Update” to install it. This often fixes network compatibility issues.
Turn LTE Off and On: Go to Settings > Cellular > Cellular Data Options > Voice & Data and switch from “LTE” to “3G” (or “4G” on some models), wait a moment, then switch back. This refreshes the data connection.

Reset Network Settings

If the quick fixes don’t work, resetting your network settings is the next logical step. This clears all saved Wi-Fi passwords, Bluetooth connections, and cellular settings, so you’ll need to re-enter Wi-Fi passwords afterward.

Open Settings.
Tap General.
Scroll down and tap Transfer or Reset iPhone.
Tap Reset, then choose Reset Network Settings.
Enter your passcode and confirm. Your iPhone will restart.

After the restart, your iPhone will re-detect the carrier automatically. This fix is particularly effective when the issue started after a recent iOS update or a trip abroad.

Check and Reseat the SIM Card

A loose, dirty, or damaged SIM card is a common culprit. If you have a physical SIM, eject the tray using a paperclip or SIM tool, inspect the card for scratches or dirt, and reinsert it firmly. If you use an eSIM, go to Settings > Cellular and tap your plan to see if it’s enabled. Sometimes toggling the eSIM off and on works. If the SIM appears damaged, contact your carrier for a replacement—this is usually free.

Update iOS and Carrier Settings

Apple frequently releases iOS updates that include bug fixes for cellular connectivity. To check for an update, go to Settings > General > Software Update. If an update is available, download and install it. Additionally, as mentioned earlier, carrier settings updates are delivered separately. You can manually trigger a check by going to Settings > General &em>About and waiting a few seconds. If a new carrier version is available, a prompt will appear.

When to Contact Your Carrier

If you’ve tried all the above and LTE still doesn’t work, the problem might be on your carrier’s side. Check if other devices on the same network have issues—if they do, it’s an outage. Call your carrier’s customer service and ask them to:

Verify your account is active and data plan is not exhausted.
Check for any blocks or restrictions on your line.
Refresh your network registration (they can do this remotely).
Confirm the correct APN settings for your iPhone (though these are usually automatic).

In rare cases, a carrier can send a new SIM card or provision your eSIM again, which often resolves stubborn issues.

Frequently Asked Questions

Why does my iPhone say “No Service” even though I’m in a coverage area?

This usually means your iPhone can’t connect to the carrier’s network. Try toggling Airplane Mode, restarting, or resetting network settings. If the issue persists, it could be a SIM problem or a temporary outage in your area.

Will resetting network settings delete my photos or apps?

No, resetting network settings only clears Wi-Fi passwords, Bluetooth pairings, and cellular settings. Your personal data, photos, and apps remain untouched.

How do I know if I’m on LTE or 4G?

On most iPhones, the status bar shows “LTE” when connected to LTE. Some carriers label it as “4G” for LTE, and “3G” for slower networks. To see your current network type, go to Settings > Cellular > Cellular Data Options > Voice & Data—it will show which networks are enabled.

Can a VPN cause LTE issues?

Yes, a misconfigured VPN can interfere with data connectivity. Try turning off your VPN in Settings > VPN and see if LTE returns. If it does, remove the VPN profile and reinstall it.

What if my iPhone is still under warranty and LTE doesn’t work?

If you’ve tried all troubleshooting and the issue persists, contact Apple Support or visit an Apple Store. They can run diagnostics to check for hardware issues. If it’s a hardware problem, it may be covered by your warranty or AppleCare+.

Does a factory reset fix LTE issues?

A factory reset (erase all content and settings) can fix deep software glitches, but it should be a last resort. Back up your iPhone first, then go to Settings > General > Transfer or Reset iPhone > Erase All Content and Settings. After the reset, set up as new or restore from backup. If LTE still fails, it’s likely a hardware issue.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

More in this bed

The whole Tech How-To bed →