Most modern smartphones technically allow you to replace a physical SIM card without powering the device down, but experts still recommend switching the phone off first. This helps avoid network recognition errors and ensures a stable connection once the new card is installed.
As Engadget reports, many current models support so-called hot-swap — changing the SIM card “on the fly”. At the same time, switching the smartphone off before the procedure allows the device to correctly re-read the operator data from the new SIM and configure the connection.
A SIM card is usually changed when switching to another operator, including a budget one, when using a local network abroad, or if the existing card is damaged. If switching the phone off is difficult, it is recommended to enable flight mode, wait about 30 seconds, replace the SIM card, and then disable flight mode. This approach restarts the mobile connection and reduces the risk of glitches.
When replacing the card, it is important to keep an eye on the device’s physical condition. Dust or moisture entering the SIM tray, or trying to insert a card of the wrong size, can damage the smartphone. An incorrectly installed SIM card can cause constant attempts to connect to the network, leading to increased battery consumption.
Owners of dual-SIM phones should carefully check which slot they are using to install or replace a card. On some Android devices, the SIM and microSD are located in the same tray. In this case, it is safer first to unmount the SD card in the settings and only then remove the tray, so as not to put stored data at risk.
For eSIM, there is no need to replace a physical card: connecting or switching to another operator is done using a QR code or the operator’s dedicated app. If, after replacing the SIM, the smartphone does not connect to the network, the first recommendation is to restart the device. If this does not help, you should check that the card has been installed correctly and that its activation with the operator has been completed.