You're probably already familiar with the SIM card, a tiny chip in your phone that connects it to your cell phone carrier of choice. For years, this chip was on a physical card that you could swap in ...

What is a SIM card used for? A SIM card, or a subscriber identity module/subscriber identification module, is a tiny memory card that contains unique information and is linked to a particular network ...

The newer eSIM technology, which is quickly becoming the standard on high-end phones, is safer and more convenient.

Learn what an eSIM is, how to set one up, and why digital SIM cards are transforming mobile connectivity. Discover the best eSIM options for travel, iPhone, and Android in this complete 2025 guide.