ESIM

An eSIM (embedded SIM) is a form of SIM card that is embedded directly into a device as software installed onto a eUICC chip. First released in March 2016, eSIM is a global specification by the GSMA that enables remote SIM provisioning; end-users can change mobile network operators without the need to physically swap a SIM from the device.^[1] eSIM technology has been referred to as a disruptive innovation for the mobile telephony industry.^[2][3] Most flagship devices manufactured since 2018 that are not SIM locked support eSIM technology;^[4] as of October 2023, there were 134 models of mobile phones that supported eSIMs. In addition to mobile phones, tablet computers, and smartwatches, eSIM technology is used for Internet of things applications such as connected cars (smart rearview mirrors, on-board diagnostics, vehicle Wi-Fi hotspots), artificial intelligence translators, MiFi devices, smart earphones, smart metering, GPS tracking units, database transaction units, bicycle-sharing systems, advertising players, and closed-circuit television cameras. A report stated that by 2025, 98% of mobile network operators were expected to offer eSIMs;^[5] they can also be purchased from fintech firms such as Revolut and Wealthfront or via online marketplaces such as Airalo.

The eUICC chip used to host the eSIM is installed via surface-mount technology at the factory and uses the same electrical interface as a physical SIM as defined in ISO/IEC 7816 but with a small format of 6 mm × 5 mm. Once an eSIM carrier profile has been installed on an eUICC, it operates in the same way as a physical SIM, complete with a unique ICCID and network authentication key generated by the carrier.^[6] 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. One common physical form factor of an eUICC chip is commonly designated MFF2.^[7] All eSIMs are programmed with a permanent eSIM ID (EID) at the factory, which is used by the provisioning service to associate the device with an existing carrier subscription as well as to negotiate a secure channel for programming.^[8]

The GSMA maintains two different versions of the eSIM standard: one for consumer and Internet of things devices^[9] and another for machine to machine (M2M) devices.^[10]