Physical SIM cards remain common for travelers and cost-conscious users switching to MVNOs, even as eSIM technology spreads. The Engadget guide notes that most current smartphones allow SIM swaps while powered on, but recommends a safer approach: power down or enable airplane mode before removing the tray. This simple step forces the phone to re-read the new card's carrier settings on startup, reducing the chance of a software-based network error.
The practical risks of swapping live are mostly physical—dirt, moisture, or a misaligned card can cause connection failures, battery drain, and overheating. Turning the phone off eliminates the software side of that risk. If you prefer not to shut down, the guide suggests switching on airplane mode, waiting 30 seconds, swapping the card, and then turning airplane mode off.
One additional warning applies to Android devices with a combined SIM and microSD tray: unmount the SD card before ejecting, just as you would an external drive. On Samsung phones, that means opening My Files, tapping the three-dot menu next to the SD card, and choosing Unmount. The overall advice is modest but useful for anyone who needs their phone back on a network quickly after a swap.