ESIM

An eSIM (embedded SIM) is a form of SIM card that is embedded directly into a device. Instead of an integrated circuit located on a removable SIM card, typically made of PVC, an eSIM consists of software installed onto an eUICC chip permanently attached to a device. If the eSIM is eUICC-compatible, it can be re-programmed with new SIM information. Otherwise, the eSIM is programmed with its ICCID/IMSI and other information at the time it is manufactured, and cannot be changed. Different mobile telephones may not support an eSIM, may have a permanently programmed, unchangeable one, or one that can be reprogrammed for any carrier that supports the technology. Phones may support physical SIMs only, eSIM only, or both.^[1]

Once an eSIM carrier profile has been installed on an eUICC, it operates the same as a physical SIM, complete with a unique ICCID and network authentication key generated by the carrier.

The eSIM standard was first released in 2016; since that point, eSIM has begun to replace physical SIM in domains including cellular telephony.