An eSIM (embedded SIM) is a SIM card that is embedded into a device, such as a smartphone or a tablet, and cannot be removed like a traditional SIM card. Instead, the eSIM is built into the device's hardware, and the user's account information is downloaded onto the eSIM via a wireless network.

eSim card technology allows users to easily switch between different mobile networks without having to physically swap SIM cards. Instead, users can activate a new mobile plan by simply scanning a QR code or using an app to download the new account information onto their eSIM.