‘No SIM Card’ or SIM Not Detected? Fixes for iPhone & Android

An hour ago it was fine. Now the status bar says No SIM, Invalid SIM or “SIM card not detected”, and you’ve got no calls, texts or mobile data. When a SIM card is not detected, the cause is usually something small, like a tray that’s shifted, a dirty contact or a settings glitch. Sometimes it’s a worn SIM, an eSIM that isn’t active, or a hardware fault.

Start by reading the exact message, because a couple of them look alike and need completely different fixes.

Which message are you seeing?

A blacklisted IMEI usually produces that last case, with the SIM detected but no registration, rather than a “No SIM” message.

The first five minutes

1. Restart the phone. A full restart reloads the modem and clears a lot of sudden “No SIM” errors.
2. Turn Airplane Mode on for 15 seconds, then off.
3. Power off, eject the tray with the SIM tool, and check the SIM is lying flat the right way round. Push the tray back in until it’s flush.
4. Wipe the gold contacts gently with a dry, lint-free cloth. No liquids, no erasers.
5. Look at the tray. A bent tray, one from a different model, or a cut-down SIM that rattles around can all break contact. Use the original tray for your model.
6. Install any system update and, on an iPhone, any carrier settings update.

iPhone: carrier settings, the line switch and network reset

Connect to Wi-Fi and open Settings › General › About. If there’s a carrier settings update, a prompt appears within a few seconds. Tap Update.

Then open Settings › Cellular (called Mobile Service or Mobile Data in some regions). Under SIMs, tap your line and make sure Turn On This Line is switched on. On a dual-SIM iPhone, check which line is set for cellular data.

Still nothing? Go to Settings › General › Transfer or Reset iPhone › Reset › Reset Network Settings. You lose saved Wi-Fi networks and VPN settings, not your data. Some iOS versions ask about eSIMs during the reset; choose to keep them.

One more thing. US models from the iPhone 14 onward are eSIM-only, and Apple has sold eSIM-only models elsewhere too, such as the iPhone Air. If you never inserted a card, “No SIM” just means no eSIM is active, and the eSIM section below applies.

Android: SIM manager, network reset and Safe Mode

First make sure the SIM is actually enabled:

• Samsung: Settings › Connections › SIM manager, and check the SIM is switched on.
• Pixel: Settings › Network & internet › SIMs, tap the SIM and turn on Use SIM.
• Other brands usually put it under Settings › Mobile network or SIM cards.

Next, reset the mobile network settings. On Samsung that’s Settings › General management › Reset › Reset mobile network settings (Reset network settings on older One UI). On a Pixel it’s Settings › System › Reset options › Reset Mobile Network Settings.

If the SIM is detected but there’s no signal, set the preferred network type to automatic (5G/LTE/3G/2G auto). Some older or regional SIMs don’t work in 5G-only modes.

Finally, boot into Safe Mode. If the SIM works there, a third-party app is getting in the way, often a dialer, a “booster” or a VPN. Uninstall recent apps one at a time.

eSIM not showing up

There’s no tray to reseat, so the approach changes:

• Check the eSIM is listed and switched on in Settings › Cellular (iPhone) or SIM manager / SIMs (Android).
• Don’t delete it while you troubleshoot. A deleted eSIM usually means getting a new profile or QR code from the carrier.
• Moved to a new phone? The eSIM on the old one is deactivated. If the transfer stalled, ask the carrier to reissue it.
• “SIM failure” just after activation often clears with a restart once the carrier finishes provisioning, which can take a little while.
• Still nothing? Ask the carrier to push a new eSIM profile, and take ID if you go to a store.

Is it the SIM or the phone?

This two-way swap is the most useful test there is. Put your SIM in another phone: if it fails there too, the SIM is faulty or deactivated, and your carrier can replace it, usually free or cheaply, with the same number. Then put someone else’s working SIM in your phone: if that shows “No SIM” as well, the problem is your phone’s tray, reader or modem.

Ask the carrier to confirm the line is active, too. SIMs get deactivated after a SIM swap request, unpaid bills, long inactivity on prepaid plans, or a number port.

The IMEI clue

Dial *#06#. A healthy phone shows its IMEI (and its EID on eSIM models) straight away. No IMEI, “null”, “unknown” or a row of zeros means the modem isn’t being read properly. That’s a hardware fault, liquid damage or a poor repair, not a SIM problem. Compare the number with Settings › General › About (iPhone) or Settings › About phone (Android) and with the box. Every place to find it is listed in our guide on how to find your IMEI number.

If the IMEI is fine and the SIM is detected but there’s no service, run a carrier and SIM-lock check and a GSMA blacklist check. A blocked IMEI can stop a phone registering on networks, as explained in what a blacklisted IMEI means.

Getting the SIM reader repaired

A known-good SIM that still isn’t detected, a missing IMEI, or a problem that started after a drop, liquid or a screen repair all point to the SIM reader, its connector or the modem. Take the phone to the manufacturer or an authorised service centre, with proof of purchase if it’s under warranty. If repairs keep failing, escalate with the manufacturer instead of paying for another fix.

Testing a used phone with your own SIM

Before you pay for a second-hand phone, put your SIM in, make a call and check mobile data. Dial *#06# and compare the IMEI with the box and the settings screen. Then check that IMEI for carrier lock and blacklist status; for US phones, a USA blacklist/barred check is worth adding. The first All-in-one Basic Info check is free: