What is eSIM Technology?

There’s a lot of buzz around eSIM technology—and rightly so. The eSIM, or embedded SIM, is changing the way people manage cellular devices since eSIM is different from traditional SIM. Unlike traditional SIM cards, which must be physically removed and replaced in an IoT device, eSIMs can be managed and switched out remotely. Since the eSIM is built into the IoT device itself, it offers greater durability than standard SIM cards. And because of its tiny size, the eSIM enables much smaller devices to connect to a wireless network.

Clearly, the eSIM offers tremendous advantages, especially to IoT managers who oversee many devices in a single deployment. But exactly what is eSIM technology? And how does an eSIM work? Here’s a quick overview of its architecture and essential functions.

eUICC (Embedded Universal Integrated Circuit Card)

A tiny integrated circuit card soldered directly to a device’s motherboard, the eUICC can store several SIM profiles and contains much more non-volatile memory than a traditional SIM card. While it can function as a SIM, the eUICC boasts more robust software capabilities, including the ability to switch between device providers and subscriptions remotely and run security-enhancing applets. The recent release of GSMA standards have allowed the eUICC market to develop more rapidly as remote provisioning becomes simpler to execute around the world.

SM (Subscription Management Platform)

A platform that connects with the eUICC, the SM serves two functions: subscription management data preparation (SM-DP) and subscription management secure routing (SM-SR). The SM-DP downloads and installs profiles and manages their security and storage. The SM-SR ensures the secure delivery of profiles between eUICC and SM-DP and oversees their status (enabling, disabling, and deleting).

Remote Provisioning

The GMSA created two sets of standards for the eSIM—one for consumer applications and the other for IoT services. Because consumer devices involve end-user interactions, they required a “pull” approach to provisioning that includes more complex features and security measures.

In IoT applications, a central operator typically manages devices from afar, so the GSMA’s IoT specifications use a “push” methodology for remote provisioning. GSMA requires the eSIM to carry a “bootstrap” profile which allows for the device’s initial connection to a network. The network operator can then push out a SIM profile to override the bootstrap. If the device needs to switch to a different network provider, the new mobile network operator can push out a different SIM profile to the chip, replacing the previous one.

Remote provisioning provides flexibility for IoT deployments because it eliminates the need to physically switch out SIM cards on hundreds or thousands of devices. A central operator can manage device profiles remotely rather than sending personnel into the field, providing tremendous savings in both time and costs.


When working with a good SIM card provider, through its design alone, the eSIM provides added security in that it is inextricably linked to the motherboard of its device. That means a hacker can’t steal the device’s identity by simply removing the SIM card and inserting another.

And while it’s still possible for hackers to take control of an eSIM-equipped device remotely, the GSMA is actively developing specifications that anticipate such security breaches. Manufacturers who want their eSIM technology to carry GSMA accreditation must adhere to guidelines from the Security Accreditation Scheme for UICC Production (SAS-UP), which oversees the production of UICCs with a special emphasis on security features.

eSIM Provides Clear Benefits Across Sectors

Consumer products like smartphones, wearables, and connected cars benefit from the eSIM’s flexible cellular connectivity and remote provisioning. For example, the eSIM is advantageous in the used-connected-car market, where SIM profiles can be easily switched out when a vehicle is sold.

Large-scale industrial IoT deployments in power plants or factories are an ideal application for the eSIM. These businesses can connect all their devices without installing (or re-installing) SIM cards and manage data collection, alerts and predictive maintenance through an IoT portal.

And when IoT devices are on the move—for example, in the container shipping industry—the eSIM provides ease of transition between cellular networks around the globe.

With its smaller size, greater ruggedness, and enhanced capabilities, the future of eSIM will change SIM technology altogether.