If you've lost the SIM ejector tool that comes with the iPhone, you can still open the iPhone SIM tray with some workarounds. Here's how.

It's a tiny metal object with a pointy tip that fits into the tiny slot on the side of the iPhone where the SIM tray is located.

Whereas the original iPhone, iPhone 3G, and iPhone 3GS all have the tray on the top. Regardless of its position, the way you remove the SIM card is exactly the same on all iPhones.

Make sure that the grooved corner of the SIM card aligns with the one in the frame of the tray to ensure correct orientation. Carefully re-insert the SIM tray back into the slot.

2. Insert the SIM card: If you have a physical SIM card, insert it into your iPhone. To do this, use a SIM eject tool or even a paperclip to open the SIM tray on the side of your device.