What is an eSIM (eUICC SIM) and why it is Transforming Global Connectivity

The terms eSIM and eUICC are often confused:

An eSIM, or embedded SIM, is a distinct physical form of SIM card (typically MFF2) whereas eUICC is a remotely programmable digital version of an eSIM or a traditional SIM card.

Instead of being physically inserted into a device using a SIM card slot, the eSIM is embedded directly into the hardware during manufacturing. They, being smaller and soldered directly onto the circuit board. eSIMs providing the benefit of miniaturisation for those devices that have limited space, need to be portable, withstand excess vibration or shock, be hermetically sealed for water ingress, or have extremely sensitive power budgets. This, however, usually means that it needs to be remotely updatable as physical changes become more difficult post deployment due to its embedded nature.

eSIMs are still therefore discrete physical SIM cards (unlike iSIMs that are securely incorporated in GSMA approved and broader functionality chipsets). eSIMs handling all of the on-SIM key security functions, including the critical hardware isolation that protects access to the secure credentials of the SIM card.

Due to their being embedded on or in the device, for future compatibility purposes, it is crucial that eSIM technology is compliant with GSMA standards and supported by remotely programmable eUICC management infrastructure. Ensuring interoperability across networks, device types worldwide and the ability to change profiles in the future if required.

This allows IoT devices to connect to mobile networks on power up, without needing to install or swap SIM cards locally in distribution centres post manufacture (although remote provisioning can be included as part of the manufacturing process).

The GSMA eUICC standards play a critical role by harmonising the secure remote provisioning of these embedded devices. This enables remote provisioning, multi-network access, and simplified management at scale for IoT devices.

For companies operating in critical sectors such as vehicle systems, security, healthcare, retail, and utilities, eSIM technology offers future flexibility, and the ability to scale securely and efficiently. For example, this can mean installing eSIMs in vehicles at manufacture with several regional connectivity profiles. The device on commissioning in its destination region communicating and receiving its primary configuration to use based on its localisation needs. For example, to optimise cost profiles for data use in certain countries, or to overcome permanent roaming restrictions.

Given the nature of IoT, where large numbers of devices are often deployed in difficult to access vehicles or telematics systems, or statically on third-party, customer sites, it is imperative that remote provisioning is reliable and managed. For example, a trusted critical IoT connectivity provider like CSL puts in place and follows essential security standards and procedures. Critical, as in the worst cases, mismanagement of these processes or a failure to understand the device contexts can lead to problems, costly mishaps or site visits.

The GSMA eUICC standards play a crucial role in the development and implementation of eSIM technology as they provide the layer of flexibility. These standards ensuring interoperability and security across the mobile industry and for device manufacturers. Allowing seamless remote provisioning and management of eSIM profiles in a coordinated way.

By adhering to the GSMA standards, IoT device manufacturers, service providers and mobile operators can confidently adopt eSIM technology knowing that devices from different manufacturers will work together seamlessly across mobile networks. Opening up a world of possibilities for IoT devices, connected cars, and other applications that require flexible and secure connectivity.

The GSMA eUICC standards are therefore the foundation that enables the widespread adoption of eSIM technology. It is important to note, however, that the GSMA eUICC standards have two distinct and primary divergences. This is to separate Consumer eSIM phone devices from IoT eSIM devices.

The main reason for this difference is due to the need to understand that IoT devices have different commissioning and operational needs to consumer phones. For example, whereas phones can be commissioned with an eSIM profile by the user or retailer via the touchcreen, there is much greater onus on remote management of IoT devices and the need to accommodate the lack of a local user, user-interface, as well as the network, and security constraints of the majority of IoT devices.

GSMA Consumer Standards: https://www.gsma.com/solutions-and-impact/technologies/esim/gsma_resources/sgp-22-v2-2-2/

GSMA IoT Standards: https://www.gsma.com/solutions-and-impact/technologies/esim/gsma_resources/sgp-32-v1-0/

The secure digital profile of traditional SIM cards is set or programmed locally during their manufacturing process. This is to the specification of the SIM commissioner. For example, the SIM card will typically have its profile set by the MNO or MVNO that is buying stock. These SIMs are manufactured in bulk and usually have high-level minimum order quantities. When a SIM is readied to be deployed with a customer, it is provisioned using a connectivity management platform (CMP). It being configured with a communications plan that sets it authorised networks, international roaming profile, cost plans and any extra security features such as specific APNs or VPN. CMPs enable these features to be managed and changed post deployment.

While these SIM cards provide surety, to change the MNO or MVNO profile requires physical replacement of the SIM card. This means rehandling the device. A procedure that is slow, costly, and often impractical at scale.

eSIM changes this as MNO and MVNO programming is handled remotely and digitally by the SIM commissioner. This means that there is greater flexibility as some of the programming is not locked into the manufacturing process.

eUICC enabled eSIMs also offer the flexibility of storing multiple network profiles on a single SIM device. It should be remembered, however, that each core MNO roaming profile comes with a cost; either a rental fee or access charge. Meaning the more profiles that are used, the higher the fixed monthly cost of the SIM card irrespective of the data usage. This is as there is an infrastructure cost to the MNOs and IMSI numbers are a valuable and finite resource to them.

Understanding the distinct features and differences between IoT eSIMs and consumer travel eSIMs is absolutely crucial in making the right choice for your mobile IoT connectivity needs:

Travel eSIMs

eSIMs for IoT devices are subject to different standards to those that are used on consumer Android, Apple iPhone, or other compatible phones or devices.

For example, travel eSIMs follow the GSMA consumer standards. As a result, they can be deployed by the phone owner or user on ‘non-user interface constrained’ devices such as smart phones.

They are becoming extremely popular for users travelling to other countries as a supplement to their existing monthly phone plan. Enabling them to add a specific international, regional, or country specific mobile data plan for a short overseas trip. This, in effect, adds a secondary SIM electronically to their smartphone device that can be controlled locally through their user phone settings or via a downloaded travel eSIM app. This is especially valuable when travelling to regions where data, SMS and voice are extremely expensive.

For example, a UK phone user with a UK SIM card (i.e. using a single network SIM from one on the UK providers or MNO carriers such as Vodafone, EE, O2 or 3) travelling to another country, may face extremely high data rates based upon their home data plan. They can instead pay for and download a native MNO profile with the time and data usage plan that suits their needs. Activating the secondary dual SIM on arrival in the region (which may be cheaper and more convenient than upgrading their existing plan). Typically, this will mean that they will have a new temporary phone number while using the travel eSIM but can remain easily contactable via cellular data on phone app systems such as email or WhatsApp (which uses mobile data and therefore allows audio or video calls to be made without notifying of the telephone number change).

It is important to note that this eSIM feature, however, is only available on newer compatible devices with eSIM support (actually eUICC), such as mobile phones, smart phones, Android devices or tablets. For example, those manufactured by Apple (iPhones and iPad), Huawei, Samsung, Google Pixel, Motorola Razr, as many older or cheaper versions of phones or tablets (including older iPads) do not support this feature.

Key Benefits of eSIM as a Dual SIM Technology for Mobile Phones and Tablets

One of the key benefits of consumer eSIM technology is the convenience it offers to users. With an eSIM, consumer users can easily switch between mobile networks and activate new plans. This flexibility not only saves time but also eliminates the hassle of dealing with and changing physical SIM cards while they are travelling. Making it easier to find the best deals or change services without physical SIM card swaps that are becoming increasingly difficult as many latest smart phone devices use embedded SIM cards only.

How are Consumer eSIMs Loaded onto Phones Using QR Codes?

eSIMs are often installed onto phones using QR codes and the device camera. This negates the need to enter long numeric codes. The process is straightforward especially when using an app which includes easy to follow instructions. A QR code is obtained from a local distributor, retailer, a travel app, network provider or directly from the phone manufacturer. Once the QR code is obtained, the option to add a new mobile plan or eSIM is selected via the settings on the phone. The phone’s camera can then be used to scan the QR code for convenience. The phone reads the information from the QR code and automatically downloads and activates the eSIM onto the smart phone or tablet device (often with a confirmation code). The primary profile can be set, switched, and controlled via the app or the phone’s settings as required. The home SIM being returned via a quick transfer process using the phone’s settings or the eSIM app on return.

How are IoT eSIMs different to Travel eSIMs?

The main difference between IoT eSIMs and Travel eSIM lies in their intended use. IoT eSIMs focussing on continuous and assured connectivity for large or medium populations of organised,  remotely managed and longer-stay IoT devices, whereas Travel eSIMs cater for the temporary international communication needs of individual consumers who are travelling shorter term.

IoT eSIMs, and their standards being specifically designed for devices that require constant connectivity, automated data exchange, and which must include secure remote provisioning (RSP) of the eSIM. IoT eSIMs being primarily used for machine-to-machine communication and IoT device connectivity in industries such as automotive, healthcare, and logistics systems, where reliable, resilient, and secure, always-on connectivity for IoT devices is essential. This is important as even those IoT devices with user interfaces such as such as Android payment terminals that have an onboard camera and touch-screen as well as a potential on-site user, will require RSP services. This is because in most cases it is highly unlikely that this eSIM task would be delegated or made accessible to a customer, either initially or on an ongoing basis.

Deploying an eSIM on an iPhone or android phone is therefore vastly different to an IoT eSIM. They, being not only subject to different GSMA standards, but also commercial conditions. For example, a traveller will only be using the traveller SIM profile for a relatively short period, whereas IoT devices or vehicles are less predictable and mass stay in a country for months or years. As IoT devices may need to stay long-term or permanently in another country or region, its ongoing connection and therefore operation, must be backed by legitimate commercial agreements. Without this, it might or will be barred or disconnected from the local networks and no longer work once it’s ‘travel’ permit is expired.

IoT eSIMs help overcome permanent or long-stay roaming issues for IoT devices, as unlike Travel eSIMs, IoT eSIMs provide tailored solutions for long-term usage via operator commercial agreements that reflect their intended IoT use cases. Also, offering better coverage through multi-network roaming, network reliability features,  cost-effectiveness, the crucially network security protection and secured, fully manged RSP.

IoT eSIMs ability to overcome permanent roaming restrictions is often also based upon the ability to localise SIM cards remotely or based upon their location. For example, in some countries such as Türkiye or Brazil, a local SIM profile is mandated for IoT devices. This means that those devices that land or are used in those regions, will need to activate a native MNO IMSI profile to avoid being barred or disconnected.

At CSL, we specialise in resilient and secure critical connectivity. For example, keeping alarms, telehealth systems, vehicles and retail networks online, no matter the conditions. eSIM technology plays a central role in this by supporting:

Remote Provisioning

Deploying or updating connectivity profiles without physical access to the device reduces operational costs and downtime — especially vital for hard-to-reach installations such as vehicles or dispersed IoT sensors.

Improving Device Design

By removing the need for a SIM slot, manufacturers can create more compact, waterproof, and tamper-resistant devices — all of which can benefit applications where miniaturisation is a priority, such as wearable technology.

Reducing Operational Complexity

Centralised eSIM management platforms streamline operations, making it easier to scale deployments, change providers, or comply with regulatory requirements.

Global roaming

eSIM can be ideal for devices that require a single SKU or move across extremely varied regions or borders; such as automotive manufacturers and telematics applications.

High Security

Secure RSP being critical as secured networks and adherence to the standards are essential with encryption being deployed at every stage of the process.

rSIM and eSIM are intrinsically harmonised as rSIM can both be deployed in the form of an embedded SIM and as an eUICC compliant profile. rSIM being compatible, fully in-tune and compliant with the current and emerging GSMA eUICC standards.

The fundamental added feature that rSIM provides, is the ability for the rSIM to monitor network connections independently of the capability of the device. Having the in-built and intelligent ability to monitor its network traffic connection and switch core network profiles under configurable parameters if a network outage is detected. This means that rSIM provides eSIM and eUICC capability, but with the key added features of self-monitoring network connections and independent profile switching through entirely discrete network pathways if all the primary profile connections are lost.

This is crucial as many IoT devices do not have this intelligence and remotely accessing devices is extremely difficult during outages. rSIM therefore augments remote SIM provisioning as it means the SIM is always connected to its central platforms and accessible.

For IoT to thrive, devices must be deployed rapidly, connect reliably, and remain flexible throughout their lifecycle. Whether it is a retail point-of-sale terminals, vehicle ADAS systems, or a smart energy meter, an eSIM allows flexible RSP moving forward.

At CSL Group, we specialise in secure, intelligent connectivity for critical applications. Our eSIM and rSIM solutions form part of a resilient IoT ecosystem designed to deliver uptime, flexibility, and global reach. By combining eSIM and rSIM technology with our connectivity management platforms, we offer:

• Global roaming with local compliance
• Multi-profile support with seamless switching
• Zero-touch provisioning
• End-to-end security across your SIM lifecycle

The Internet of Things also depends on fast, secure, and reliable connectivity. eSIM enables IoT devices to be deployed anywhere and operate securely. This is particularly valuable for sectors including:

• Smart metering and energy monitoring
• Retail point-of-sale and payment terminals
• Vehicle and automotive systems
• Industrial automation and remote asset management

With eSIM and rSIM, you gain flexibility without sacrificing control — a perfect fit for CSL’s strategy to deliver always-on, intelligent connectivity. Whether you are deploying 10 devices or 100,000, our managed eSIM solutions ensure your infrastructure is future-ready, reliable, and compliant to global and local needs.

At CSL Group, we are at the forefront of deploying eSIM-based solutions that support mission-critical connectivity across the UK, Europe, the USA, Asia and beyond. Helping vehicle manufacturers, fleet operators and payment terminal manufacturers deploy flexible eSIM solutions that are future proofed and can be reliably serviced post deployment. Please therefore contact us to find out how eSIM can help transform your operations.