Reviewed: September 23, 2026. If Android suddenly says No SIM, SIM not detected, Invalid SIM or stops showing your carrier, first determine whether the phone cannot see the SIM at all or can see it but cannot register on the mobile network. Those are different failures, and treating them the same can lead to unnecessary resets.
A missing SIM can come from a temporary software fault, a card or tray that is not making proper contact, a damaged or unsupported SIM, an eSIM transfer problem, carrier-side activation, or device hardware.
1. Check whether Android actually detects the SIM
On Pixel-style Android, open Settings > Network & internet > SIMs. If your carrier appears but the SIM is disabled, turn on Use SIM. Google’s current Pixel connectivity guidance specifically recommends this check. Galaxy and other Android phones may label the menu SIM manager, Mobile network or Connections.
If the carrier entry is grayed out and Android reports no SIM, focus on detection: the physical card, tray, eSIM profile or device. If the SIM is visible and enabled but mobile data is the only service failing, use our Android mobile data troubleshooting guide. If calls are the main failure, use our Android calls, SIM and carrier guide.
2. Restart before changing network settings
Restart the phone and check SIM status again. Google notes that a restart may be required to obtain mobile service after inserting a SIM. This is safer than deleting an eSIM, resetting networks or erasing the device.
3. Confirm your exact model supports the SIM you are trying to use
Device configuration varies by model and market. Google states that U.S. Pixel 10, Pixel 10 Pro and Pixel 10 Pro XL models do not support a physical SIM and use eSIM instead. Do not force a tray that is not part of your device configuration.
Compatibility can also change across generations. Google says some older SIM cards are not supported on Pixel 8 and later phones; an unsupported card can trigger a message telling you to contact the carrier for a new SIM. If an old card fails only after moving it to a newer phone, replacement may be more appropriate than resetting Android.
4. Check Airplane mode, but distinguish it from No SIM
Airplane mode disables wireless radios, so turn it off if enabled. However, a persistent No SIM message is not the same as having mobile service disabled. If Android cannot recognize the card, focus on detection.
5. Reseat and inspect a physical SIM safely
Power the phone down if your manufacturer recommends it. Use the correct eject tool, keep it straight, and do not force a resistant tray. Check that the nano-SIM sits flat and matches the tray orientation.
Google’s current Pixel guidance says to inspect a physical SIM for bending or damage and request a replacement from the carrier if damaged. If it has dirt or dust, wipe it gently with a microfiber cloth before reinserting it. Samsung likewise advises gentle cleaning and warns against forcing a tray.
6. Cross-test the SIM and phone
When possible, test your SIM in another compatible unlocked phone and test a known-working compatible SIM in your phone. This is one of the strongest diagnostic splits.
- Your SIM fails in multiple compatible phones: the card, account or carrier activation becomes the leading suspect.
- Multiple known-working SIMs fail in your phone: device configuration, compatibility or SIM-reader hardware becomes more likely.
- Your SIM works elsewhere but not in this phone: verify device compatibility and carrier provisioning before assuming hardware failure.
7. Treat eSIM transfer and activation separately
An eSIM has no tray or contacts to reseat. Check whether the profile appears under SIM settings and whether it is enabled. If you recently moved to a new phone, complete the carrier-supported transfer or activation flow.
Google’s Pixel support says an unsuccessful eSIM transfer should be tried again and persistent transfer problems should be escalated to the carrier. Avoid deleting a working or partially configured eSIM as an early troubleshooting step because downloading it again can require carrier authorization.
8. Check carrier activation and protection features
A SIM can be physically recognized yet fail to activate after a device change. Contact the carrier if the problem began after moving the SIM, replacing the phone, porting a number, changing service or traveling internationally. Ask whether the line is active, whether the SIM/eSIM is correctly provisioned, and whether any SIM-swap or device-protection feature is blocking activation.
9. Reset mobile network settings only after isolation
A network-settings reset can help when the SIM is detected but cellular registration or configuration is corrupted. It is not a mechanical repair for a broken SIM reader. Read the confirmation screen first because reset scope differs by Android manufacturer and version.
If the broader symptom is internet failure rather than SIM detection, our Android internet troubleshooting hub can help isolate Wi-Fi, DNS and cellular problems.
10. Know when to replace the SIM or service the phone
Ask the carrier for a replacement when the card is bent, damaged, repeatedly disappears in more than one compatible phone, or the phone explicitly reports that the SIM is no longer supported. Hardware service becomes more plausible when several known-working compatible SIMs are not detected in the same phone, the tray or reader is damaged, or the problem follows impact or liquid exposure.
If the phone is also overheating or rebooting, diagnose those symptoms separately. Our Android overheating guide covers that path.
What not to do
Do not factory-reset the phone before testing SIM recognition, another SIM and carrier status. Do not scrape SIM contacts, bend the card, force the tray, copy APN values from random websites or repeatedly delete an eSIM profile without knowing how it will be restored. APN changes cannot make an undetected physical SIM appear.
Bottom line
For an Android phone showing No SIM, first check whether Android recognizes and enables the line. Restart, confirm the exact device supports your SIM type, inspect and reseat a physical card, then cross-test the card and phone. Treat eSIM activation separately and involve the carrier when transfer, activation or provisioning is the likely cause. If multiple known-working SIMs remain invisible in the same device, hardware service is more rational than a factory reset.
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