An eSIM, or embedded SIM, is a digital version of a traditional SIM card that is built directly into a device. Unlike physical SIM cards, which can be removed and replaced, eSIMs allow users to switch mobile carriers and plans without needing to change a physical card. This technology is commonly found in smartphones, tablets, and wearables. eSIMs offer several advantages, including the ability to store multiple carrier profiles on a single chip. This means users can easily switch between different networks, making it convenient for travelers or those who want to manage multiple plans. Additionally, eSIMs help save space in devices, allowing for slimmer designs.