IoT Glossary

What is a multi-SIM?

Multi-SIM technology makes it much easier to achieve constant connectivity and for devices to switch between regional operators.

What is Multi-SIM?

Traditional SIM cards are generally assigned to a single operator (single network SIMs). And therefore provide just one connectivity option for each IoT device. A multi-SIM approach makes it much easier to achieve constant connectivity. Multi-SIM can be achieved by installing two SIMs in a device or, more commonly, a multi-network SIM card that can hold multiple profiles. All of these options enable devices to swap to a better quality network, and for devices on-the-move to switch between in-country or regional operators.

Here’s the lowdown on multi-SIM technologies and how they can support your IoT projects.

What is a multi-SIM?

Multi-SIM devices

This refers to devices that are designed to house two or more physical SIM cards. For IoT applications, multi-SIM solutions are most often used in devices such as fleet trackers and industrial equipment. Usually, one SIM card connects the device to your core mobile network, while another card connects to your back-up provider. This can help ensure ongoing connectivity in case of a signal outage with your core provider.

Multiple networks on a single SIM

A multi-network SIM is similar to a single network SIM in that it is procured from a primary operator, but the profile is built to allow access to multiple networks per country. In most key markets this means there is choice between 2, 3 or sometimes 4 or 5 networks per country.

Multiple profiles on a single SIM

A SIM profile comprises all the information required for a device to connect to a mobile network operator, including the file system, operator access keys and International Mobile Subscriber Identity (IMSI). A standard SIM card usually only has enough memory capacity for one profile. In other words, you get one connectivity option per-SIM.

Only a minority of devices are able to house and support more than one SIMs. IoT deployments are typically bound by cost, size and energy efficiency so keeping component count and size down is often essential. So for businesses that need a multi-SIM solution, instead of having multiple physical cards in a device, the best option usually involves a single SIM that can support multiple profiles although a multi-network SIM is a good compromise.

One way of doing this is with a SIM card that incorporates a type of technology known as eUICC (Embedded Universal Integrated Circuit Card). With this, a single SIM card can host several profiles at once. You can also add, remove and manage these profiles remotely.

What is multi-IMSI?

In a similar way to eUICC (eSIM), multi-IMSI technology lets you store multiple mobile network operator profiles on a single SIM. It also lets you swap between operators remotely. The main practical difference is that with Multi-IMSI, you tend to have a single core mobile network operator, but multiple subscriber identities, so it’s a useful way to take advantage of roaming where coverage with your main provider is thin.

Multi-IMSi vs eUICC

However, with multi-IMSI, your fundamental relationship with your core provider stays the same. If you want to move to a completely new provider, you would generally need to change the physical SIM. With eUICC by contrast, if you want to change provider completely, you can potentially lift your whole IoT estate to a new network provider, without having to replace a single SIM card.

What are the benefits of multi-SIM cards?

Reliable and future proof connectivity

For applications such as transport and logistics, end-to-end supply chain connectivity from a single mobile network may not be possible. While multi-network SIMs are a very strong alternative, the ultimate flexibility and future proofing comes from multi-IMSI or best of all eUICC SIMs. eUICC enables businesses to deploy different SIM profiles to match their operating requirements. This can include a mix of multi-network SIM profiles for different countries or regions and a country specific single network SIM profiles option. These options give businesses the ultimate control over reliability, cost management and control while minimising the need for retrofitting physical SIM cards after deployment.

Your business may plan to upgrade its IoT connectivity solution. Or you might want to move to a completely different mobile network operator. With a multi-sim, multi-network or multi-profile solutions (specifically eUICC), you can manage these changes over the air (OTA), without having to recall hundreds or thousands of devices from the field. In industrial settings, IoT devices may be deployed in difficult-to-access locations, or are hermetically sealed for environmental protection. eUICC allows you to change your connectivity settings without the need for SIM card retrofitting.


At the production stage, eUICC helps you avoid having to allocate different SIM cards for different regions and use cases. Instead, each device gets a standardised chipset, and you upload appropriate profiles onto each one. This can help make roll-out both faster and cheaper. The right solution also makes it feasible for businesses to switch services and take advantage of alternative providers at any point during the entire lifecycle of the device.

Whether it’s for fixed deployments, assets on the move or dispersed across the globe, Wireless Logic can help you deploy precisely the right SIM technologies to meet your future business needs. For more information, explore our IoT solutions.

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For an expert assessment of your connectivity needs and to discover the best fit M2M options for your business, speak to Wireless Logic today.

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