iSIM and the Future of Connected Devices

When the pioneering electronic musician Brian Eno was commissioned to compose the startup tone for Windows 95, it initially seemed like a simple gig – the required sound was to be no more than three seconds long. Instead, he poured months of work into the project. Eno eventually created more than 80 “microsongs”, each deviating by fractions of a millisecond. When he ultimately returned to longer-form compositions, Eno was overwhelmed, “it seemed like oceans of time”.

In the shrunken confines of mobile hardware development, the success or failure of a product can be determined by infinitely small distances. What may seem negligible to the naked eye can be the result of years of dedicated effort from industrial designers. As consumer expectations for mobile hardware grow in sophistication, original equipment manufacturers (OEMs) continue to explore new ways to pack more features into smaller and smaller devices.

Space-saving innovations like the eSIM have revolutionized the form factor of new mobile hardware and paved the way for the rise of connected products like smartwatches and health trackers. Now, the iSIM, or “integrated SIM,” promises to take this concept even further, delivering a viable SIM format that takes up almost no additional space in the body of a device.

The eSIM age

In 2025, the mobile industry body GSMA detailed some of the most significant obstacles to furthering eSIM adoption. Some – the availability of eSIM-enabled devices, or access to 5G data – were global in scope, and dependent on a range of geopolitical factors.

Others, like public education on the benefits of eSIM, are simpler to address. Even in regions where the technology is readily available, many users are still unfamiliar with the advantages eSIMs bestow.

The launch of the eSIM-only iPhone Air and iPhone 17 in September 2025 marked a turning point. The world’s bestselling smartphone line has now done away with SIM cards altogether, resetting consumer expectations on mobile connectivity in the process. Google and Samsung are expected to follow suit.

While the rollout of eSIM can feel new, the technology has been a mainstay of commercial operations and the IoT industry for over a decade. As public awareness continues to grow, and OEMs push for ever more compact SIM formats, the next generation of SIM is already in development. In 2024, there were an estimated 800,000 iSIM-connected devices in the world. Current research suggests a more than tenfold increase by 2028.

The iSIM promises all the functionality of an eSIM in an even smaller package. With eSIMs currently poised to become the dominant SIM format worldwide, what benefits do iSIMs hold? And why haven’t they experienced the same popularity as eSIMs?

What is an iSIM?

Both eSIMs and iSIMs are microchips embedded within the hardware of a device that can store multiple software-based SIM profiles. The key difference is the location and size of the chip: eSIMs are stored on a dedicated eUICC chip, which is usually around 5x5mm. An iSIM is instead located within the device’s central processing unit (CPU), a status known as “System on a Chip” (SoC).

SIM card, eSIM, and iSIM: the key differences

• SIM card – The SIM profile is stored on a physical card, which is inserted and removed via a slot on the device. One SIM profile can be stored per card.

• eSIM – The SIM profiles are stored on a tiny microchip, known as an eUICC, which is soldered into the body of the device. A single eUICC chip can store several SIM profiles.

• iSIM – The SIM profiles are embedded on a specialized element within the device’s processor. Unlike eSIMs, iSIMs do not require a dedicated external eUICC chip. Multiple iSIMs can be stored within the element. Functionally, iSIMs occupy no extra space and are limited only by the size of the processor.

Do we need iSIMs?

Replacing a cumbersome SIM tray and card with an embedded chip allows OEMs to cram additional other features into their devices. No longer having to accommodate these pieces of plastic frees up space for new features and improvements, from larger batteries to more powerful cameras.

The iSIM promises to be even smaller, offering OEMs a slight but significant advantage. While manufacturers may have led the push towards eSIM, consumers and businesses are now taking full advantage – software-based SIM profiles offer several advantages, from freeing up space for device design, to reducing power consumption, simplifying the manufacturing process and making management and distribution of connectivity profiles far simpler.

Why iSIMs matter now

While iSIMs have yet to break into the collective consumer consciousness, they’ve long been considered a potential tool in the Internet of Things (IoT) industry. The eSIM was initially developed for IoT in 2012, before making its way into the consumer mobile space.

The IoT sector embraced eSIM as it solved a key problem at the heart of the industry: how to deploy, manage, and recall vast amounts of connected devices, around the world, at scale. The rise of eSIM enabled a concurrent boom in the IoT and wireless connectivity space. Now, the industry stands at a precipice: the number of connected devices is set to grow sharply over the coming years, with an expected market valuation of $1.5 trillion by 2028.

Facing this future requires unearthing efficiencies at every stage of the industry, including SIM connectivity. At this crucial juncture, IoT firms are beginning to take iSIM seriously – shrinking the SIM to an SoC format could reduce power consumption and environmental impacts of the mobile industry.

By eliminating the need for external SIM cards or eUICC chips, iSIM technology has the potential to:

• Reduce bill of materials (BoM) costs

• Lower power consumption

• Limit waste

• Reduce the environmental impact created by the manufacture, packaging, and transport of SIM cards and eUICC components

The iSIM may also create further efficiencies for OEMs, as it furthers their ability to create components in-house, eliminating the need for external eUICC or SIM card providers.

Instead, SIM functionality can now be integrated within the device’s main processor. This also allows hardware manufacturers to transition from external suppliers to components built in-house.

Another potential efficiency benefit of iSIMs is In-Factory Profile Provisioning, or IFPP. This concept further simplifies the manufacturing and supply chain processes of mobile devices by allowing OEMs to pre-load CPUs with active iSIM profiles, delivering ready-to-connect cellular devices straight from the factory.

iSIMs and hardware design

The release of the iPhone 17 in September 2025 was a moment OEMs had been building to for years. Hardware companies have been major drivers of the eSIM transition among consumer devices, motivated by the desire to eradicate bulky SIM cards and trays from the design process. In the highly competitive mobile hardware market, every square mm counts. At just 5.6mm thick, the dimensions of the new iPhone Air would be impossible with a physical SIM card.

Under these circumstances, iSIMs may be a good option because they promise to take this one step further. By eliminating the need for an external SIM element, they may usher in a new era of mobile hardware formats, shapes, and functions.

In late 2025, the wearables startup Oura Health raised $900m in funding. Their flagship product, the Oura Ring, mimics many of the health and fitness monitoring capabilities of much larger smartwatches in a minuscule package. While the Oura Ring is yet to feature cellular connectivity, it reflects a growing demand for wireless connectivity in every aspect of daily life. In the same way that eSIMs catalyzed the smartwatch market, iSIM technology may unlock a new generation of connected device types.

Security and lifecycle management

As with all technological shifts of this scale, there are a few obstacles to overcome before iSIMs can play a meaningful role in consumer electronics. One of the most pressing is their role in digital security.

While eSIMs provide several security advantages over physical SIMs, the safety of iSIMs is less clear, especially at this early stage. Unlike a plastic SIM card, it’s physically impossible for an eSIM or iSIM to be lost or stolen. This alone has made eSIMs a popular choice for business customers, as it reduces the risk of sensitive material going missing from employees’ mobile devices.

While the same is true of iSIMs, pertinent security and privacy concerns remain:

• Certification: The leading mobile industry body, the GSMA, maintains a set of principles governing the secure usage of eSIMs. Currently, iSIM connectivity is less regulated by the GSMA, though iSIM has been certified. Security standards are less defined than with eSIM. The same is true of other proposed SIM formats like Soft SIMs. As demand grows, however, some iSIMs are being developed that satisfy the GSMA’s eUICC security requirements.

• Adoption: iSIMs are a younger technology than eSIMs (launching roughly six years later), and as a result, face several early-stage hurdles to secure viable functionality and widespread adoption. The technology is as yet untested in large-scale deployments and widespread consumer usage.

Conversely, proponents of iSIM argue that the SoC format imbues them with particular security advantages: eSIMs vastly improved on the security of SIM cards by moving the sensitive SIM information from an easily transferable plastic card to an internal chip, soldered into the device. By being built into the processor itself, an iSIM takes this principle a step further, in theory becoming even harder to isolate and remove. The GSMA calls this the “secure enclave” concept – the idea that the iSIM is ring-fenced within the main processor, defined by independent processing and encryption functions.

Software formats like eSIM and iSIM feature several digital security controls, including secure credentials storage and internal encryption.

Like eSIMs, iSIMs are transferred, managed, and recalled digitally, a process known as remote SIM provisioning (RSP). Not only does this provide a massive efficiency boost for mobile operators and IoT companies, it also allows for heightened security. RSP enables companies to instantly distribute security updates to all SIMs worldwide. Expert RSP partners like 1GLOBAL enable “Zero Touch” SIM distribution – the safest and most accurate method of delivering SIM profiles to devices. Unlike manually sending a SIM card or requiring the user to download a digital SIM, Zero-touch provisioning remotely "pushes" the SIM profile to the device, with no effort from the end-user. This is the most secure form of SIM provisioning available, eliminating the risk of human error or interference from the process.

Whichever format is used, an eSIM, iSIM, or SIM card requires a secure SIM provisioning service to be truly safe for private or commercial use.

The future of embedded connectivity

While eSIMs are on track to become the world’s most popular eSIM format within a couple of years, the future of iSIM is less certain. Despite backing from the GSMA and keen interest from OEM manufacturers, SoC SIMs still face numerous barriers to widespread adoption.

If it does catch on, the technology has the potential to reshape the commercial and consumer mobile landscape. GSMA experts highlight its “unique opportunities for never-before-seen applications in smaller and low-end devices”, while noting that it’s unlikely to usurp eSIMs “in the majority of cases”.

Concurrently, other SIM formats are being explored that remove the physical form factor entirely. “Software SIMs” exist entirely digitally, requiring no hardware components.

Whether SIM card, eUICC, SoC, or software-only, a SIM is only viable when supported by a reliable and secure SIM provisioning and management service. The current popularity of eSIM is made possible by rigorous regulation from industry bodies like the GSMA, and state-of-the-art SIM management services from eSIM experts like 1GLOBAL. A new report from Juniper Research notes that “eSIM vendors must develop trusted partnerships with manufacturers to ensure adoption of iSIM connectivity services once it becomes demanded in the market.”

1GLOBAL RSP

Addressing the next phase of telecommunications requires greater alignment between OEMs, mobile operators, and customers. New SIM formats can only become successful when they earn public trust – doing so requires a secure, viable, and intuitive RSP foundation. More specifically, it requires one with the capability to execute these processes on a global scale, in line with booming demand for wireless services.

1GLOBAL is a GSMA-certified eSIM provider and multinational MVNO, operating a single core network across 190+ countries. Since 2018, we’ve delivered carrier-grade RSP solutions for OEMS, MNOs, and IoT companies around the globe.

Contact us today to learn more about how 1GLOBAL is preparing IoT and consumer mobile brands for the future of connectivity.