Embedded SIM: How It Works, Pros/Cons, and 5 Best Practices

What Is an Embedded SIM? 

An embedded SIM is a SIM that is built into a device rather than being a removable plastic card. Unlike traditional SIM cards, which need to be inserted into a slot, an embedded SIM is soldered directly onto the device’s circuit board.

Embedded SIMs are widely used in smartphones, tablets, smartwatches, and IoT devices, offering flexibility and improved durability compared to traditional SIMs. 

Embedded SIMs are often confused with eSIMs, but they are not the same. According to the official GSMA definition, eSIM is a SIM that can be remotely provisioned, making it possible to switch carriers or network profiles without physically replacing the SIM card. This is enabled by the eUICC standard. Embedded SIMs often include eUICC technology, and in this case they are also eSIMs. But some embedded SIMs cannot be remotely provisioned and are locked into a specific network and mobile profile.

How Embedded SIM Technology Works

An embedded SIM (embedded subscriber identity module) is a microchip permanently soldered onto a device’s motherboard during manufacturing. Unlike traditional SIM cards that are inserted into a slot, the embedded SIM is integrated directly into the device’s circuitry, eliminating the need for a physical card or tray. It contains the same components and functionality as a standard SIM, storing subscriber identity and authenticating the device on mobile networks.

Once installed, the embedded SIM is programmed with a mobile profile, typically during production or initial device setup. If the embedded SIM supports the eSIM standard (eUICC), it can be remotely provisioned with a different mobile profile. 

The embedded SIM design improves reliability and durability, especially in rugged or compact devices where exposure to dust, water, or mechanical wear is a concern. Embedded SIMs are commonly used in IoT deployments, wearables, and other connected devices where space, security, and long-term connectivity are critical.

Embedded SIM vs. eSIM (SIM with eUICC)

Embedded SIM and embedded universal integrated circuit card (eUICC) technology are two distinct concepts which are often confused.

An embedded SIM is a SIM chip that is permanently embedded in a device’s motherboard. Unlike traditional SIM cards, it cannot be physically removed or replaced. Embedded SIMs may or may not include eUICC technology that allows users to switch between carrier profiles remotely.

An eSIM is a SIM that includes eUICC (embedded universal integrated circuit card)—a software specification that enhances SIM functionality by enabling remote provisioning and management of operator profiles. With eUICC, users can switch between carrier profiles on a single SIM, without having to replace the physical SIM. This is particularly beneficial for international travelers, IoT deployments, and enterprise-managed devices.

Key differences between embedded SIM and eSIM with eUICC

Adoption and industry support

The GSMA has standardized eUICC technology to ensure compatibility across mobile networks and device manufacturers. This has led to growing adoption in smartphones, smartwatches, connected cars, and industrial IoT. 

While most modern embedded SIM implementations include eUICC capabilities, not all carriers fully support remote profile switching, limiting some of its advantages in certain regions. As eUICC adoption increases, embedded SIM technology will become even more versatile, enabling seamless connectivity across consumer and enterprise applications.

Embedded SIM vs. Removal SIM Cards

Embedded SIMs and removable SIM cards serve the same purpose—connecting devices to mobile networks—but they differ in design, functionality, and usability. While traditional SIMs are removable and require manual swapping, embedded SIMs are built into devices. 

Here is a comparison of key differences between the two technologies:

1. Form factor: A removable SIM card is a removable chip on card that must be inserted into a device. In contrast, an embedded SIM is permanently built into the device’s motherboard, eliminating the need for a SIM tray.
2. Space and durability: Since embedded SIMs are soldered onto the device, they save space, enabling thinner designs and larger batteries. They also improve durability by eliminating a physical slot, improving resistance to dust and water.
3. Security: Embedded SIMs offer improved security as they cannot be physically removed, reducing the risk of SIM card theft or cloning. Digital provisioning also allows organizations to manage multiple devices securely.
4. Compatibility and adoption: While most carriers support removable SIM cards, eSIM based embedded SIM adoption is still growing. Not all devices that include embedded SIMs also support eSIM, forcing users to continue relying on traditional removable plastic SIMs.

Pros and Cons of Embedded SIM Technology (Without eUICC)

Pros

• Space-saving design: Since embedded SIMs are built into the device, they eliminate the need for a SIM tray, allowing for thinner devices, larger batteries, and better waterproofing.
• Enhanced security: Embedded SIMs cannot be physically removed, reducing the risk of theft, cloning, or unauthorized swapping.
• Better durability: Unlike physical SIMs, embedded SIMs are soldered onto the motherboard, making them resistant to damage from dust, water, or accidental removal.
• Efficient device management: Organizations and IoT providers can manage multiple devices, updating carrier profiles without physical intervention.

Cons

• Device lock-in: Some devices may be locked to specific carriers, restricting the flexibility embedded SIMs are meant to provide.
• No physical swapping: Unlike traditional SIMs, which can be quickly replaced if a network issue arises, embedded SIMs require a digital reconfiguration, which may take more time.
• Compatibility issues: Older devices and some budget models do not support embedded SIMs, making them less accessible for all users.

Devices Supporting Embedded SIMs

Embedded SIM technology is increasingly integrated into a range of devices, offering improved connectivity and flexibility. Some common device categories supporting embedded SIMs include:

• Smartphones: Many flagship models from Apple, Samsung, Google, and other manufacturers support embedded SIMs, allowing dual-SIM functionality without a second physical SIM slot.
• Tablets: Devices like Apple’s iPad Pro and some Samsung Galaxy Tab models use embedded SIMs for cellular connectivity without requiring a physical SIM.
• Smartwatches: Wearables such as the Apple Watch and Samsung Galaxy Watch use embedded SIMs to stay connected independently of a smartphone.
• Laptops: Some models from Lenovo, HP, and Microsoft Surface devices feature embedded SIM support, enabling mobile connectivity without a physical SIM.
• IoT and automotive devices: Embedded SIMs are widely used in smart home devices, connected cars, industrial IoT applications, and fleet management systems, allowing seamless remote connectivity.

As embedded SIM adoption continues to grow, more devices are expected to support this technology, reducing reliance on traditional SIM cards.

Embedded SIM vs. iSIM: Understanding the Next Evolution

While embedded SIMs have already improved flexibility and connectivity, integrated SIMs (iSIMs) represent the next step in SIM technology. Both eliminate the need for traditional plastic SIM cards and embedded sims, but they differ in implementation and capabilities.

What is an iSIM?

An integrated SIM (iSIM) takes the concept of an embedded SIM further by embedding SIM functionality directly into a device’s main processor or system-on-chip (SoC). Unlike embedded SIMs, which are separate chips soldered onto the motherboard, iSIMs are fully integrated into the device’s core hardware.

Key differences between embedded SIM and iSIM

Benefits of iSIM technology:

• Further miniaturization: Since iSIMs are integrated into the SoC, they free up even more space, allowing for smaller, more efficient devices.
• Lower power consumption: iSIMs consume less energy than embedded SIMs, making them suitable for IoT devices that require long battery life.
• Stronger security: By integrating SIM functionality directly into the processor, iSIMs offer improved protection against tampering and cyber threats.
• Simplified manufacturing: With no need for a separate SIM component, iSIMs reduce production costs and complexity.

Challenges of iSIM adoption:

• Limited availability: While embedded SIMs are already widely used, iSIM adoption is still in its early stages and not yet common in consumer devices.
• Carrier and device support: The industry is still working on broader carrier compatibility and standardization for iSIM technology.

4 Best Practices for Implementing Embedded SIM

Here are some important practices to consider when using embedded SIM technology.

1. Optimize Device Design for Embedded SIM

When integrating embedded SIM technology into a device, manufacturers should consider design factors that improve performance and usability. Since embedded SIMs are soldered onto the motherboard, eliminating the SIM tray can create additional space for larger batteries, better waterproofing, or improved antenna placement.

Thermal management is also critical, as embedded SIM chips operate within the main circuitry. Ensuring proper heat dissipation and shielding from electromagnetic interference helps maintain stable performance. Additionally, designing for seamless carrier switching by integrating intuitive software support in device settings improves the user experience.

2. Leverage Embedded SIM for IoT and Enterprise Use Cases

Embedded SIM technology is particularly valuable for IoT deployments and enterprise applications, where managing a large number of connected devices can be challenging. 

Organizations should leverage eUICC to enable flexible SIM provisioning and simplify device management. In industrial IoT and automotive applications, it is especially critical to allow devices to switch dynamically between networks, ensuring continuous service or cost savings in different regions. Enterprises deploying embedded SIMs with eUICC capabilities should work with carriers that support flexible provisioning and multi-network access.

3. Properly Manage Multiple Profiles 

An embedded SIM that supports eUICC can hold multiple carrier profiles, allowing a device to switch between them without changing hardware. However, not all embedded SIMs have this capability—some are limited to a single fixed profile. Devices that do support multiple profiles must manage them carefully to ensure reliability and compliance. 

To manage multiple profiles effectively, device firmware should integrate with the local profile assistant (LPA), which handles profile installation, activation, and deletion. The user interface should allow users (or administrators, in enterprise scenarios) to view and switch profiles securely. In enterprise or IoT environments, remote management platforms can automate profile updates based on network performance, policy rules, or device location.

4. Understand Regulatory and Compliance Requirements

Different regions have regulations governing embedded SIM usage, including carrier policies, security standards, and privacy considerations. Manufacturers and service providers should ensure their devices comply with global standards such as the GSMA’s eSIM specifications for remote SIM provisioning.

In some countries, SIM activation requires identity verification or compliance with local telecommunications laws. Understanding these requirements before deployment can prevent service disruptions and ensure a smooth user experience. For enterprise and IoT applications, ensuring embedded SIM security through encryption and authentication protocols is essential to protect against unauthorized access and network vulnerabilities.

Managing Embedded SIMs at Scale with Flolive

floLIVE offers eUICC services to its customers, as part of its Connectivity Management Platform (CMP). eUICC services are integrated with the CMP to provide a holistic, unified solution from a single vendor, single platform and single contract. We distinguish between two types of eUICC service ‘flavors’:

• M2M
• Consumer 

The RSP platforms for supporting both M2M and Consumer eUICC services are hosted in secure data centers that have been audited and certified by the GSMA, according to the GSMA SAS-SM accreditation standards as defined in the GSMA SGP.16 standard. There are currently two data centers:

• Austin, TX, USA
• London, UK 

The physical security, network security, personnel and organization, data management and operational processes at the above sites were assessed and approved against the GSMA FS.08 and GSMA FS.17 requirements. In addition, the design and implementation were validated against the GSMA SGP.11 specification. As required by the GSMA’s SAS-SM scheme, these data centers are re-audited every two years.

Key features and benefits:

• Eliminates SIM production and shipping costs: Enables optimized pricing models for various applications.
• Supports high usage: Ideal for high-data-volume applications (GB per SIM).
• Supports new market segments such as travelers, wearables, and enterprise
• mobility solutions.
• Facilitates seamless connectivity for MiFi devices, laptops, and fleet management systems.
• Easy activation via QR code, poster QR for consumer eSIM and remote activation for M2M eSIM.
• Ability to transfer eSIM profiles between devices.
• Simplifies enterprise and service provider operations with automated provisioning.

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