6 reasons why your iPhone won't detect the SIM card
There are countless reasons why your iPhone may not recognize the SIM card. However, we can summarize them into a few basic causes:
- Incorrect SIM card insertion.
- Scratched or broken SIM card due to impact.
- Water damage causing internal moisture, making the device incompatible with the SIM card.
- Software malfunction in the iPhone.
- Locked iPhone model unable to recognize the SIM card.
5 suggestions to quickly and effectively fix the iPhone SIM card detection issue
Depending on the cause, users may be able to troubleshoot the issue of iPhone not recognizing the SIM card at home or may need to take it to device repair centers. If it's minor, simple troubleshooting steps can be considered as follows.
- Check the SIM card and SIM tray
Firstly, you need to check whether your SIM card is intact, not cut improperly, or scratched.

Therefore, for a new SIM, you need to be extremely careful when cutting it to fit the phone's SIM tray because even a slight deviation can render the SIM unusable.
If the SIM card is heavily covered in dirt, you should also clean its surface to ensure a better fit with the device. During the SIM card cleaning process, handle it gently as it contains many delicate circuits that can easily be damaged.
While checking the SIM card, take the opportunity to inspect whether the SIM tray is corroded or damaged in any way. This could also be a relatively high factor causing the iPhone to not recognize the SIM card.
- Power off your iPhone and restart it
When the RAM memory is overloaded due to using multiple apps simultaneously, it can easily cause the functions of your iPhone to slow down, making the device less efficient. Over time, this becomes a common reason why the iPhone doesn't recognize the SIM card.
To fix this, simply power off your iPhone for a while and then turn it back on.
- Toggle Airplane mode on/off on your iPhone
Toggling Airplane mode on/off on your iPhone is similar to quickly resetting the device. This action will refresh the phone's network connections, and if the iPhone recognizes the SIM card again afterward, it's a good sign.

To toggle Airplane mode on/off on iPhone, swipe up from the bottom of the screen, then tap on the airplane icon to toggle it on or off as usual.
- Check the origin of your iPhone
Currently, the iPhone market offers genuine VN/A versions, international versions, and Locked versions, which not everyone can distinguish, leading to the risk of buying a Locked device or intentionally purchasing one.
Buying a Locked iPhone means accepting that some features won't work, including SIM card recognition.
- Reset network settings for your iPhone
Due to the usage habits of many users, sometimes you may accidentally reset your device, leading to changes in network settings on your phone. To fix this issue, you can follow these two basic steps:
– Step 1: Go to Settings > General > Reset.
– Step 2: Select Reset > Reset Network Settings.

If you've tried all the methods above and your iPhone still doesn't recognize the SIM card, the issue is likely hardware-related. In this case, the most effective and safest solution is to take your phone to the nearest and most reputable repair center for timely assistance.