Understanding eUICC vs eSIM: Key Differences Explained

December 3, 2024

4:30

IoT Connectivity

You would be forgiven for thinking that eUICC and eSIM are the same thing, given that they are being used interchangeably by a lot of media sites and blogs. The reality is, however, that they are two different technologies.

In this article, we will clearly define what eSIM and eUICC truly are and discuss some of the distinct advantages they provide.

So, what exactly does eSIM mean?

SIM stands for Subscriber Identity Module and is often used to refer to the small card-shaped chip that is inserted into smartphones and other mobile-connected devices. The SIM enables a device to be recognised on the carrier network and identified by the number associated with it.

Traditional SIM cards have been through a few iterations throughout the lifecycle of the technology. It’s perhaps hard to imagine now, but the first SIM actually resembled a credit card in size and weight! This is the first form factor of SIM, or 1FF as it is referred to in the industry.

Subsequent forms of SIM have been the mini-SIM (second form factor, or 2FF), micro-SIM (3FF) and the nano-SIM (4FF).

There is now also another SIM form factor, the MFF2, which are embedded SIMs, soldered onto the device circuit board. This is the preferred form factor for connected devices that move a lot of work in very harsh conditions.

SIM Form Factors

Confusion arises when people assume that an embedded SIM (MFF2) has remote provisioning capabilities (eUICC) because both MFF2 and eUICC are referred to as eSIM. So which one is eSIM?

To avoid any confusion, we suggest the following way of looking at the definition:

"eSIM is the whole service − SIM + eUICC + platform;
eUICC is the software that allows provisioning."

In fact, eSIM is a technology that can be present regardless of form factor. Take the relatively new iPhone XR for example, it accommodates a removable SIM but also has an eSIM service built-in, allowing users to purchase a plan from another carrier and use it alongside their contracted calls, messaging and data plan.

In summary, eUICC is the software enabling a SIM to remotely provision mobile network operators, whereas eSIM represents the entire service ecosystem. Both are independent of the MFF2 form factor.

What does eUICC do that a UICC can’t?

To better understand eUICC, it can be useful to compare it with its predecessor, highlighting the differences between eUICC and eSIM.

The Universal Integrated Circuit Card (UICC) does a lot more than just the Subscriber Identity Module (SIM). In fact, it runs the SIM application whilst also storing various pieces of information such as the user’s contacts list, enabling the use of mobile data and managing data roaming across multiple carriers.

So, what is the difference between UICC and eUICC?

eUICC, or Embedded Universal Integrated Circuit Card, often leads to confusion with the embedded SIM MFF2 among businesses. However, eUICC is actually a SIM component that can be integrated into any SIM form factor to facilitate the eSIM service, including embedded options.

A key advantage of an eUICC-enabled SIM card is its capability to conduct over-the-air (OTA) provisioning of various network operator profiles from a centralised management hub. After provisioning, the SIM profiles on the card can be managed remotely and deleted if required.

Over-the-air provisioning and management provide a degree of flexibility that was unattainable prior to the advent of eUICC. Devices equipped with an eSIM service can be transitioned in large numbers almost instantaneously, and we are merely at the beginning of this technology's evolution.

What does Velos IoT offer?

Velos IoT provides eSIM solutions crafted to unlock the full potential of your business.

Our ULTIMATeSIM solution delivers reliable, seamless, and secure global connectivity. Tailored for IoT service providers, OEMs, and large enterprises, it empowers their services and devices to function worldwide.

By harnessing top-tier coverage from leading carrier networks, ULTIMATeSIM facilitates both global and local connectivity across diverse SIM form factors and industrial standards.