SIMs, eSIMs and iSIMs: the difference and why it matters

SIM cards or ‘Subscriber Identity Modules’ are familiar to most of us as the small, removable cards we insert into our mobile phones.

They store data that uniquely identifies us to the mobile network, which allows us access to the communication services we have contracted.

However, as a means of identifying and connecting the billions of devices that now make up the Internet of Things (IoT), the SIM as we know it needs to change.

From SIMs to eSIMs to iSIMs

The SIM continues to provide secure access to the network – over time it has adapted by getting progressively smaller and integrated within the device, and with iSIM technology it has disappeared altogether. Combine this with advanced software that detects the status, location and data usage of the SIM and you have a highly secure and simple way to connect billions of IoT devices across the globe.

But does having a SIM fixed in a device mean limiting customer choice? No, eSIMs (embedded Subscriber Identity modules) can be updated over the air through a process called Remote SIM Provisioning (RSP). This makes the process of connecting a device much simpler and provides far more choice for the customer. It also ensures that they always get the best connection wherever they are. iSIM (Integrated Subscriber Identity modules) takes this one step further with the SIM becoming a secure component within the communications module or microprocessor chip and is far more flexible than its predecessors, allowing network access to be configured over the air after the device has been manufactured.

When you combine the advantages of eSIM and iSIM with specialist cellular IoT networks like NB-IoT and LTE-M, the world of IoT opens up even further – enabling a new generation of small, battery-powered devices that work indoor and out. These are all connected on the same secure cellular mobile networks that we use every day.

The advances in SIM technology – like eSIM and iSIM – retain all the benefits of security and access to global networks, but with form factors getting increasingly smaller, it enables customers to build more compact and lower-powered devices. It also means that customers can select their preferred network operator based on the location where the device will be in use, rather than where it was manufactured.

For many IoT customers, this flexibility is essential as they expand into new markets where regulation and data security require them to use different network providers.

And it doesn’t stop there. The new industry standard SP.31/.32 will make the switching process even simpler, giving customers even more choice and control over how they connect their IoT devices across the world.

If you’d like to find out more about SIM technology and what combination is best for you, why not take a look at Vodafone’s white paper ‘The difference between SIM cards, iSIM and eSIM/eUICC.’