The physical SIM card lasted thirty years as the dominant technology for mobile authentication. Its replacement, the eSIM, has been in commercial deployment for less than a decade and is already being succeeded by formats that eliminate dedicated SIM hardware entirely.
Understanding where mobile connectivity is heading requires tracing the trajectory from physical SIM to eSIM to the technologies currently in development, and recognizing the pattern: each generation of the technology moves the authentication and provisioning layer deeper into the device while making the user experience progressively more invisible.
The Current State: eSIM Adoption Accelerating
The eSIM is the standard against which the next generation of connectivity will be measured. For readers who want to understand the technical foundation of how the current system works before examining what replaces it, Holafly has built a comprehensive resource explaining what an esim is that covers the eUICC standard, the provisioning architecture, and the dual SIM operational model in accessible language.
The GSMA projected eSIM connections in consumer devices to surpass 3.4 billion in 2025, with growth accelerating across Asia, Latin America, and Africa as mid-range device manufacturers integrate support into their hardware.
The US market completed a significant inflection point when Apple removed the physical SIM tray from iPhone 14 models sold domestically, normalizing eSIM-only devices for the first time in a major Western market.
The iSIM: Eliminating the Last Dedicated Hardware
The iSIM, or integrated SIM, represents the next step in the trajectory. Where the eSIM is a discrete chip soldered to the circuit board, the iSIM integrates SIM functionality directly into the device’s main System on Chip, sharing the processor’s secure enclave for cryptographic operations rather than maintaining a separate secure element.
The practical implications of this integration are significant. Removing the eUICC as a discrete component reduces board space requirements, lowers manufacturing costs at scale, and improves power efficiency by eliminating the data bus between the SIM chip and the processor.
For wearables, IoT sensors, and ultra-thin form factor devices where every cubic millimeter of board space represents a meaningful engineering constraint, iSIM makes connectivity feasible in device categories where eSIM is still marginally too large.
Qualcomm integrated iSIM functionality into its Snapdragon 8 Gen 2 processor. Apple’s custom silicon has included integrated SIM functionality in Apple Watch since Series 3.
The question is not whether iSIM comes to mainstream smartphones but when the ecosystem of carrier support and regulatory approval catches up with the hardware capability.
Soft SIM: The SIM as Pure Software
Beyond iSIM, researchers and standards bodies are exploring Soft SIM implementations where the SIM exists entirely as a software layer within the device’s trusted execution environment, with no dedicated hardware at all.
The authentication credentials are stored and processed within the same secure enclave that protects payment data, biometrics, and cryptographic keys.
Soft SIM creates challenges that the hardware-based eUICC was specifically designed to address. The security model for physical SIM hardware relies on the tamper resistance of a dedicated secure element.
Software-only implementations must achieve equivalent security guarantees through cryptographic and architectural means rather than physical constraints.
The certification and audit requirements for Soft SIM are correspondingly more complex, which is why the technology remains in research and pilot phases rather than commercial deployment.
The GSMA has published preliminary specifications for Soft SIM under the SGP.31 framework, and several telecom research consortiums are running trials.
Commercial deployment in premium smartphones is projected for the late 2020s, contingent on regulatory frameworks that have not yet been established in most markets.
Satellite Connectivity: The Network Layer Revolution
The SIM evolution addresses device-side authentication architecture. The parallel revolution happening at the network layer is equally significant: direct satellite connectivity to consumer devices, which eliminates the dependency on terrestrial cellular infrastructure entirely in low-coverage areas.
Apple’s Emergency SOS via satellite, launched with the iPhone 14, demonstrated that satellite communication is feasible from a consumer smartphone without additional hardware.
The service uses low Earth orbit satellites for emergency messaging and location sharing in areas without cellular coverage.
SpaceX’s Starlink Direct to Cell partnership with T-Mobile and international carriers is taking this further: full broadband cellular service delivered directly to standard LTE-capable devices via satellite, without any modification to the device or subscription.
The service began beta testing in 2024 and is progressing toward commercial availability with initial speeds suitable for messaging and eventually voice and data.
AST SpaceMobile is building a similar capability with its BlueBird constellation, targeting direct cellular broadband to unmodified smartphones at speeds sufficient for video streaming.
The Convergence: Software Authentication Plus Ubiquitous Connectivity
The trajectory converges on a device where authentication is handled entirely in software within a trusted execution environment, and connectivity is available from any combination of terrestrial cellular, WiFi, and low Earth orbit satellite infrastructure, all managed by a software layer that selects the optimal connection source without user awareness.
In this model, the concept of a carrier-specific SIM profile becomes less architecturally meaningful. What replaces it is an authentication framework tied to the device and the user’s identity rather than to a specific network operator’s chip. Carrier relationships become software agreements rather than hardware dependencies.
What This Means for Users Now and in Five Years?
For users today, the practical takeaway from this trajectory is simple: the transition from physical SIM to eSIM is the last hardware change they will need to make.
Devices purchased with eSIM support are compatible with the provisioning infrastructure that will serve them for the foreseeable future, because the next generations of the technology are backwards compatible at the network layer.
For travelers in particular, the eSIM transition has already delivered the most meaningful near-term benefit: the ability to activate local data plans in over 200 countries before departure, without physical SIM swapping, keeping the home number active in parallel.
The iSIM and Soft SIM transitions will make this process more seamless at the hardware level, but the fundamental capability exists today.
The Regulatory Dimension
The evolution beyond eSIM is not purely a technology challenge. It is a regulatory one. National telecommunications regulators built their frameworks around the assumption that subscriber identity is tied to a physical artifact, either a SIM card or an eSIM chip, that can be audited and attributed. Software-only authentication and satellite-direct connectivity challenge both assumptions.
The EU’s work on eSIM portability regulation, which addresses consumers’ right to transfer profiles between devices without carrier obstruction, is one early example of regulatory frameworks catching up with technology.
Similar frameworks will be needed for iSIM and Soft SIM before they achieve mainstream commercial deployment in regulated markets.
The Longer Arc
Zooming out further, the thirty-year history of SIM technology is a story of authentication moving progressively closer to the device and further from the network, while the user experience simplifies at each step.
The SIM card required physical presence at a carrier store. The eSIM requires a QR code scan. The iSIM will require nothing more than accepting terms on a screen. The Soft SIM may require nothing at all, with carrier selection handled automatically based on location and pricing algorithms.
The endpoint of this trajectory is connectivity that is genuinely invisible to the user: always available, always authenticated, always selecting the optimal network, and requiring no conscious management. The technology to achieve this exists in prototype form today.
The path to commercial deployment runs through standards bodies, regulatory approvals, and the slow cadence of hardware refresh cycles that govern when new technology reaches the majority of active devices.
With many years of professional experience within transnational corporations in different industries, Richard Jaimes has had the opportunity to lead people and organizations, investigate future topics, create strategies and innovations, consult senior management and translate insights into business advantages. Richard is also a long time senior consultant with Quantumrun Foresight.
