What is eUICC? – IoT Uncovered

Quick eUICC definition:

eUICC stands for embedded universal integrated circuit card (eUICC). It refers to the software component of eSIM that runs on a UICC and provides the capability to store multiple network profiles that can be provisioned and managed over-the-air (OTA). The term eUICC is often used to mean the whole physical card or chip.
To solve the historically painful process for mobile phone customers changing network suppliers, the GSMA introduced the eUICC specification to enable users to change their network provider without physically swapping the SIM card.

Although it was envisaged that eUICC SIMs would primarily be in the form of soldered chips or implemented within a system on a chip (SOC), eUICC SIMs can be any SIM form factor.


The terms eSIM and eUICC are often used interchangeably, with eSIM meaning an eUICC-enabled SIM and eUICC referring to the eSIM architecture. The terms are often mixed up because embedded SIMs (eSIM) need eUICC technology to be able to switch and localise as you cannot physically swap the SIM.

Learn more about eSIM

Key requirements for an IoT SIM

The SIM in an IoT device has a critical job to ensure secure, reliable connectivity between the device and the enterprise data centre. Zero-touch connectivity starts when the device is installed and continues until the end of its lifespan.

At the start of any IoT project, it’s important to forecast how long the device should operate in the field. The SIM needs to be robust enough to last the lifetime of its paired device. And it should be able to receive over-the-air commands to update software and security or change networks. That’s a big ask – and not many SIMs can do it.

The SIM might stay connected to one mobile network or roam onto others. It might need to change networks to achieve better connectivity or avoid roaming restrictions. And that’s where multi-IMSI SIMs come into their own – housing multiple mobile network operator profiles on a single SIM, eradicating the need to physically swap SIM cards or enter new network information. So, how is eUICC different?

Benefits of eUICC for IoT

The main benefit of eUICC for IoT is that it provides the capability to store multiple mobile network profiles  on a single SIM. These network profiles can be provisioned and managed easily over-the-air. With eUICC, you have peace of mind that your connectivity will remain stable.

eUICC is especially useful for enterprises with hundreds of thousands of devices. They have the buying power and resources to change network providers at regular intervals to achieve better deals.

For smaller businesses, using eUICC to switch providers isn’t usually a realistic option today. But future technical and commercial developments may create more cost-effective and practical solutions.

Given the long lifespan of IoT devices, it’s sensible to use eUICC-compliant SIMs so you can take advantage of any future network changes or market opportunities.

Risks of eUICC for IoT deployments

The over-the-air capability to swap providers means eUICC should be ideal for IoT devices, which may be inaccessible or have embedded SIMs (or both).

But in practice, eUICC for IoT is complicated by both technical and commercial issues.

When a consumer wants to swap network providers using eUICC, they can connect their device to Wi-Fi so the new provider can download their profile to the SIM.

Yet most IoT devices don’t have a user interface, access to Wi-Fi connectivity or a user to operate the device. This means both current and new providers must cooperate to make the swap.




Switching MNO profiles with an eUICC SIM

A network provider who wants to support eUICC must provide:

  • eUICC-compliant SIMs that can be remotely provisioned
  • A Remote SIM Provisioning Platform (RSP)

The RSP is comprised of two elements:

  • SM-DP (Subscription Manager-Data Preparation) stores and manages the network profiles
  • SM-SR (Subscription Manager-Secure Routing) handles secure communications with the eUICC SIMs, enabling the SIMs to be provisioned remotely

A swap between two providers also requires a deep technical integration between their systems – at the SM-SR level. An integration of this type can cost hundreds and thousands of pounds and take months to implement. It also demands specific development expertise which can be difficult to find.

With around 700 network operators globally, most operators are unlikely to have integrations with many of the other network providers. Some don’t support eUICC at all.

Network transfers on standard eUICC take time to agree and implement. If you’re changing providers because of poor IoT connectivity, time is something you don’t have. The new provider is responsible for delivering the connectivity service – that means a new contract, a new management platform, a new support system.

If you have multiple providers for your devices, you’ll have multiple contracts, management platforms and support systems. You may still have contracts with previous providers, if their contracts hadn’t expired before you swapped.

And what if the new IMSI fails to connect in some locations?

When the new provider takes over, the previous provider’s IMSIs are removed from the SIMs. So, if the new IMSI fails to connect, there’s no way back…the devices remain disconnected until someone can physically sort them out.

Questions you should ask your SIM provider

When selecting a SIM provider and connectivity platform, you need to understand how they will aid the potential switching process and affect your systems.

  1. What measures are in place to secure connectivity?
  2. Approximately how much data will be collected and communicated by the device?
  3. Where will the devices be deployed? Across multiple regions? In remote places?
  4. Will the device be fixed and stationary, or portable?
  5. Can I afford for devices to have periods of downtime if connectivity drops? E.G telehealth device
  6. How much maintenance can we afford in terms of time and cost?
  7. Does your provider operate their own SM-SR to enable dynamic profile management?
  8. Is there the ability to bring your own carrier (BYOC), whilst having the flexibility to access other networks?
  9. Does the eSIM have multiple bootstraps to provide network redundancy?

The future of eUICC

There are customized, advanced eUICC solutions available from providers such as Eseye that harness the benefits of eUICC in a useable way for commercial IoT. Providers who invest in the infrastructure and expertise required to meet the eUICC specification – both the SIM and the RSP (in particular the SM-SR functionality) – show they’re serious about offering the future-proofed solutions that IoT businesses need. This is an area that Eseye has been investing in for several years, building on its extensive multi-IMSI SIM capability.


IMSI: An International Mobile Subscriber Identifier (IMSI) identifies a user or device on a particular network. The IMSI is one of the key data items stored on a SIM. Traditional SIMs contain a single IMSI, provided by the selected network operator. The IMSI is installed onto the SIM during manufacture and ties the SIM to the operator’s network (the home network). Depending on the roaming agreements that the operator has in place, devices can roam onto other networks, but the only way to change network operator or service provider is to physically replace the SIM with a SIM from a new provider.

Multi-IMSI SIM: A Multi-IMSI SIM can store multiple IMSIs, enabling devices to switch to different networks without physically changing the SIM. Connectivity providers offer multi-IMSI solutions with different levels of sophistication, functionality, and security. Some solutions can use over-the-air updates to download additional IMSIs and remotely manage the IMSIs on a SIM.

eSIM: eSIM technology provides the same functionality and security as conventional SIMs, with enhancements that enable:

  • Secure, over-the-air updates for remote provisioning and management of profiles
  • Storage of multiple network profiles on the SIM

SIMs of all form factors can be enabled to use eSIM.

eUICC: eUICC stands for embedded Universal Integrated Circuit Card (eUICC). It refers to the software component of eSIM that runs on a UICC and provides the capability to store multiple network profiles that can be provisioned and managed over-the-air (OTA). The term eUICC is often used to mean the whole physical card or chip.

Although it was envisaged that eUICC SIMs would primarily be in the form of soldered chips or implemented within a system on a chip (SOC), eUICC SIMs can be any form factor.

SIM: SIM stands for Subscriber Identity Module. Although it’s often used to mean the whole physical card or chip, a SIM is technically one part of the UICC. It’s responsible for securely storing data, including:
• The Integrated Circuit Card Identifier (ICCID), which identifies the physical SIM itself
• The International Mobile Subscriber Identity (IMSI), which identifies the mobile network to which the SIM is subscribed
• Credentials and cryptographic security keys that identify and authenticate a subscriber on a network

A SIM passes identity and authentication information to a cellular modem. The modem performs the actual connection to the network.


Global IoT
Made Easy

Connectivity You Can Trust

This 2021 IDC Vendor Spotlight, sponsored by Eseye, examines:

  • How it’s possible to simplify global IoT connectivity and remove the complexity, while still delivering security, affordability, and control
  • Why Eseye’s next-generation eUICC and unique SM-SR technology differentiates it in the market

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Lucy Holden Senior Marketing Executive

Lucy is passionate about how IoT is used for the greater good to change the world and save lives.

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