Seeing a "No SIM" or "SIM card not detected" message on your Nothing Phone (3) can stop you from making calls or using mobile data. It's a common hiccup that's usually easy to fix, often caused by a loose card, a software bug, or a simple setting.
Restart Your Phone
A quick restart is the best place to start. It clears out temporary glitches that might be confusing the phone's modem. Just press and hold the power button until the power menu pops up, then tap "Restart."
If the screen is unresponsive, you can force restart it. Press and hold the Volume Down and Power buttons together for about 10 to 15 seconds until you see the Nothing logo appear on the screen.
Check the SIM Card and Tray
Power your phone off completely before you do this. Use the SIM ejector tool that came in the box to pop out the tray. Take a close look at the SIM card's gold contacts for any scratches, dirt, or corrosion.
Gently wipe the contacts with a clean, dry microfiber cloth. While the tray is out, give it a quick blow or use a can of compressed air to dislodge any dust. Carefully reinsert the tray, making sure the SIM card is seated correctly and the tray clicks fully into place.
Toggle Airplane Mode
This is a fast way to refresh your phone's connection to the network. Swipe down from the top of the screen twice to open the full Quick Settings panel. Tap the Airplane Mode icon to turn it on, wait about 10 seconds, then tap it again to turn it off.
Verify SIM is Enabled in Settings
Sometimes a SIM can get accidentally disabled in the software. Open the Settings app and go to Network & Internet or Connections. Look for an option like SIM cards or Mobile network.
Tap into that menu and make sure the switch next to your SIM card is toggled on. If you're using dual SIMs, check that the correct one is set as the default for calls and data.
Update Your Software
Bugs in Nothing OS can sometimes interfere with the modem. Keeping your phone updated is crucial. Go to Settings > System > System update and tap "Check for update."
If an update is available, download and install it. I'd recommend doing this over Wi-Fi and making sure your phone has a good charge first. After the update, restart your phone to complete the process.
Reset Your Network Settings
This will erase all your saved Wi-Fi networks, Bluetooth pairings, and cellular settings, but it won't touch your personal files. It's a strong step for network-related issues.
To do this, navigate to Settings > System > Reset options. Tap on Reset Wi-Fi, mobile & Bluetooth and confirm. Your phone will reboot, and you'll need to reconnect to Wi-Fi and re-pair Bluetooth devices afterward.
Check for Carrier Settings Updates
Your mobile carrier occasionally pushes small updates that help your phone connect properly to their network. These usually install automatically, but it's worth checking.
After ensuring you have a mobile data connection (even if it's weak), go to Settings > Network & Internet > SIMs. Tap on your carrier's name and look for a "Carrier settings" or "Access Point Names (APN)" option. If an update is pending, you'll often see a prompt here.
Manually Select Your Network
Your phone usually picks the best network automatically, but this process can sometimes fail. You can force it to search again. Go to Settings > Network & Internet > Mobile network.
Tap on Advanced and then look for Choose network or Network operators. Tap "Search" and select your carrier's name from the list that appears. Don't choose one that says "Forbidden."
Test the SIM in Another Device
This tells you if the problem is with the SIM card itself or with your Nothing Phone (3). If you have access to another unlocked phone, power it off, insert your SIM, and turn it back on.
If the other phone also says "No SIM," then the issue is almost certainly with the SIM card. You'll need to contact your carrier's support to get a replacement SIM sent out, which is usually free.
Consider an eSIM
The Nothing Phone (3) supports eSIM technology. If your physical SIM card is old or you're having persistent hardware-related issues, switching to an eSIM can be a great permanent fix.
Contact your carrier to see if they support eSIM activation for your plan. They can guide you through scanning a QR code in your phone's settings to download the digital SIM profile directly.