Why Use a Multi-IMSI SIM for Your IoT Deployment

SIM, Security, Multi IMSI, Global SIM

Whether it’s asset tracking, expansive agricultural installations, or fleet management, deployments that cross multiple geographical, regional, or national boundaries often need coverage beyond what a single provider can offer. The challenge, then, is that most basic SIM cards are only able to support a single provider.

As time rolls on, IoT deployments are only becoming more and more complex. A recent survey by 451 Research found that 61% of enterprise IoT deployments utilize two to five vendors to operate, with larger companies ($10B+) involving as many as 13. Given that companies are expected to spend an average of $2 million on IoT each year through 2024, businesses are constantly re-evaluating their vendors. This is particularly true when multiple connectivity solutions are in the mix.

Fortunately, there is an answer. SIMs with multi-IMSI capability offer a promising solution for businesses seeking enhanced global connectivity, increased reliability, cost optimization, and simplified logistics in their IoT deployments.

Autonomous Electric Van semi truck car driving on a highway, asset tracking

What is an IMSI, and Why Should I Care About It?

The International Mobile Subscriber Identity (IMSI) is a unique identifier found on SIM cards that enable connectivity operators to authenticate and authorize users to access their networks. Essentially, you can think of an IMSI as the digital key or carrier code that lets a cellular tower know whether a device is allowed to connect to a specific telecom provider.

The issue faced by many within the IoT sphere, however, is that most traditional SIM cards from telecom operators are tied to a single network provider and their tower infrastructure. This significantly limits connectivity options, making it challenging to switch networks in order to ensure reliable coverage in different regions.

Multi-IMSI capability allows SIM cards to access multiple profiles, enabling devices to switch between different networks based on availability, quality, or cost. The end result is the more consistent, reliable, and carrier-agnostic connection that many IoT deployments rely upon. This is particularly ideal for installations that move in and out of any particular carrier’s coverage area.

What about eUICC?

To some, this may sound similar to many of the benefits granted by eUICC SIMs, yet there are some subtle differences between eUICCs and multi-IMSI SIMs. eUICC allows for over-the-air (OTA) switching between connectivity networks, much like multi-IMSI SIMs, with the added benefit that they can also switch over to different carriers once your contract with an existing provider runs its course. This means that you won’t need to replace an eSIM, which is soldered directly to the board of your IoT device, just to switch between networks.

Though eUICC SIMs do incorporate multi-IMSI capabilities at a fraction of the size of a traditional SIM, the technology to push new subscription profiles onto an eSIM can present multiple challenges. For one, not all devices are capable of utilizing an eSIM, placing eUICC out of the reach of many deployments. 

Furthermore, Multi IMSI functionality with an eUICC SIM can get expensive at scale; there is no automated switching based on coverage availability, and connecting to multiple networks is not assured. Each carrier needs to agree to integrate with each other’s systems to be able to swap profiles, and unless there is a financial reason for them to do so (say, for a massive-scale project or government organization), they may not be likely to agree to such a deal.

The Soracom Difference? Subscription Containers

At Soracom, we recognize that if your devices aren’t connecting, then your project isn’t working, so ensuring that you have every option to transmit your data is of the utmost importance. That’s why every Soracom SIM card and eSIM employs subscription containers to help expand your options for connectivity.

Subscription containers allow you to add multiple subscription plans to the individual SIM. Adding more subscriptions allows your SIM to have additional sets of IMSIs and their corresponding keys. These optional subscriptions unlock expanded coverage to more countries and networks, as well as grant access to potentially more cost-effective data rates.

With subscription containers, Soracom’s SIMs and eSIMs can host multiple carrier subscriptions based on your plan and availability, which can cover all the major carriers in a region. This means that users don’t need to get new SIMs as their plans expand and evolve, as any specific provider’s coverage in an area changes, pricing shifts, or for whatever reason.

Some of the benefits of this structure include:

  • Enhanced Global Connectivity – access to the strongest cellular internet connections in an area across multiple carriers or even national borders. 
  • Automatic Network Switching further implementation opens seamless connectivity even in areas where a single network may be weak or unavailable.
  • Reliable Uptime for Data Transfers – reduced risk of downtime or unplanned system shutdowns
  • Cost Optimization – deployment always selects the most affordable connectivity option
  • One SIM for Everything – quick and easy start/scale with a SIM (or eSIM) that can connect to almost every carrier in the area

Moreover, while many multi-IMSI and eUICC SIMs are issued with all of their profiles locked, Soracom’s subscription containers offer the flexibility to change and add new IMSIs at any point in their lifecycle. This level of autonomy allows users unprecedented control and freedom as it pertains to which carriers their devices can connect with.

Soracom Subscription container diagram, Multi-IMSI SIM

How Does It Work?

Subscription containers are delivered wirelessly to Soracom SIMs through an OTA update, meaning as long as your device is connected using a Soracom SIM, you can add a subscription container to it regardless of its location. Simply log into the Soracom User Console, select a SIM, and add a subscription. Soracom takes care of packaging subscription details (such as IMSI and authentication keys) into the subscription container and sends the container directly to your device.

Once your device receives the container, it will be automatically added to the SIM, and the profile applet will then check to see if your device is currently located in an area supported by the new subscription. If it is, it will automatically switch subscriptions. By using the Soracom API, you can even do this across multiple SIMs and groups.

A Plan for the Future

To take full advantage of the subscription container function and ensure reliable coverage wherever your SIMs are located throughout North America, we are proud to introduce our newest coverage plan – Plan-US-Max. This plan offers subscribers access to the widest range of connectivity providers to date, notably including the three largest telecom providers in the country – AT&T, T-Mobile, and Verizon.

Best of all? This plan doesn’t require any new equipment or complex installation. Simply download your new subscription container(s) OTA for existing plan01s SIMs/eSIMs – even UICC SIM cards. This, too, can be managed through API so users can manage their deployment at scale rather than affecting each individual SIM.


Got a question for Soracom? Whether you’re an existing customer, interested in learning more about our product and services, or want to learn about our Partner program – we’d love to hear from you!