A single IMSI SIM card may work in limited or localized use cases, but when devices are deployed across multiple regions or require mission-critical connectivity, gaps in coverage and compliance risks quickly appear. This is why multi-IMSI SIMs are becoming a cornerstone of modern IoT connectivity strategies.
What is an IMSI, and what makes a SIM “multi-IMSI”?
IMSI stands for International Mobile Subscriber Identity. It is a unique identifier stored on a SIM card that enables a mobile network operator (MNO) to recognize and authenticate a subscriber. On a traditional SIM card, a single IMSI is stored, and the device is tied to one operator and its roaming partners. While roaming has long been used to extend coverage beyond a single operator’s footprint, it is far from perfect when it comes to IoT.
A multi-IMSI SIM takes a very different approach. Instead of being limited to a single IMSI, it can store multiple IMSIs, each associated with different mobile operators. The SIM can switch between these identities automatically depending on coverage, performance, or cost requirements.
For IoT deployments, this flexibility is a major advantage. Unlike consumer devices, which often remain within the same region or only roam occasionally, IoT devices are frequently deployed across borders, operate in remote or challenging environments, and require persistent data transmission for monitoring, tracking, or control.
Imagine a logistics provider shipping goods across Europe or a utilities company with smart meters scattered across rural and urban areas. In both scenarios, relying on a single IMSI means relying on one operator’s roaming agreements, which may not cover every location effectively. By contrast, multi-IMSI SIMs provide the ability to utilise multiple roaming agreements across several IMSI´s, ensuring the device has access to a wider global network.
Why single IMSI SIMs fall short
The limitations of single IMSI SIM cards become clear when examined through the lens of IoT requirements. First, coverage is a major challenge. Even the largest operators cannot offer complete coverage across entire countries, let alone across multiple markets. A single IMSI solution leaves devices vulnerable to dead zones where neither the home operator nor its roaming partners provide service.
Second, resiliency is compromised. If the home network experiences an outage, devices using a single IMSI have no fallback and simply go offline. For mission-critical IoT applications such as healthcare devices, emergency response systems, or energy infrastructure monitoring, downtime is unacceptable.
Multi-IMSI vs. eUICC: not the same thing
Multi-IMSI is often used in conjunction with eUICC. Both technologies involve multiple operator profiles, but their functionality and operational impact are very different.
An eUICC SIM can store multiple operator profiles, giving businesses long-term flexibility and future-proofing for IoT deployments. Switching between operators typically involves downloading and activating a new profile, which is managed through standardized GSMA systems. While this process requires coordination with operators, it ensures security, interoperability, and a reliable framework for scaling IoT solutions globally.
Multi-IMSI SIMs work differently. Instead of downloading profiles, multiple IMSIs are preloaded onto the SIM by the connectivity provider. Switching to the optimal IMSI can be done automatically based on the country or network the device will try to connect to. The customer benefits from seamless coverage and reliability while the provider manages the relationships with multiple mobile operators in the background.
At Com4, we combine both technologies to give our customers the best of both worlds. Multi-IMSI delivers day-to-day flexibility and resilience, while eUICC ensures long-term freedom to change providers if needed. We can also use this operationally with new and alternative profiles we have access to.
The benefits of multi-IMSI SIMs
The advantages of multi-IMSI SIMs for IoT are extensive.
First, they provide connectivity through multiple roaming agreements, rather than relying on a single one. This is particularly important in regions with strict restrictions on permanent roaming.
Third, multi-IMSI simplifies vendor management. Instead of negotiating dozens of contracts with different MNOs, businesses can rely on a single connectivity partner that has already established the necessary agreements. This reduces complexity, cuts down on operational overhead, and speeds up time to market.
Fourth, scalability becomes much easier. IoT deployments often start small and expand rapidly. With multi-IMSI SIMs, businesses can scale from hundreds to millions of devices without renegotiating or re-integrating with new operators along the way.
By using non-steered SIMs, devices automatically connect to the strongest available network in each location, ensuring reliable coverage across large-scale deployments without manual intervention.
Com4’s multi-IMSI connectivity
At Com4, we specialize in providing IoT connectivity that is resilient, compliant, and scalable. Our multi-IMSI SIMs are designed to give customers complete flexibility while keeping operations simple. With a single Com4 SIM, IoT devices can access multiple international operator profiles, each with different roaming agreements.
Equally important, Com4 removes the complexity of managing multiple operator relationships. With us, customers benefit from a single global contract, a single vendor relationship, and a unified platform for connectivity management. This reduces the burden on internal teams and provides peace of mind that connectivity will be both reliable and compliant wherever devices are de
Make sure your multi-IMSI solution is truly multi-IMSI
At Com4, that is exactly what we deliver. Our multi-IMSI SIMs are designed to support IoT businesses wherever they operate, ensuring uninterrupted service, compliance with local regulations, and the flexibility to scale globally. For enterprises deploying connected solutions across borders and industries, Com4 provides the connectivity foundation that ensures devices stay online, secure, and cost-efficient.
If your business is ready to take IoT connectivity to the next level, Com4’s multi-IMSI SIMs provide the smart, reliable, and future-proof solution.
