What is an M2M SIM card?

M2M is the abbreviation for machine-to-machine and means that machines communicate with each other or exchange data. An M2M SIM card in turn ensures that machines and other devices have access to the internet or mobile phone network to transmit data. In this overview, we explain what M2M SIM cards in general are all about.

An overview: Features and special characteristics of M2M SIM cards

An M2M SIM card is a SIM card that enables devices such as alarm systems, vending machines, trucks and many others to establish a connection to the mobile network and transmit data via it.

A "normal" SIM card, such as the one you know from your own smartphone, is only suitable to a limited extent. Although M2M SIM cards do not differ visually from SIMs for smartphones, they pursue a different purpose and offer correspondingly different functions. In the context of M2M communication, for example, it is important that the device can establish a data connection anywhere and at any time. It can't do that with a normal SIM card; instead, it needs an M2M SIM card.

Standard & Industrial: Different forms and properties of M2M SIMs

In order to meet the different requirements of end devices and machines, SIM formats have been and continue to be constantly developed. To ensure that the SIM cards themselves take up as little space as possible, the size has been significantly reduced, leaving more room for other components if required. Basically, a distinction is made between the SIM card formats mini, micro and nano. There are also embedded SIMs that are soldered directly into the modem as a chip. In addition to the standard version, the different formats are also available as "Industrial SIM". This more robust variant is designed, for example, for an extended temperature range and a longer service life.

SIM formats of the whereversim
Available SIM Formats
Operating Temperature
Read/write Cycles
Data Retention
Standard M2M SIM

-25°C to +85°C

Read/write Cycles


10 years

Industrial M2M SIM

-40°C to +105°C


10 years at -40°C to +105°C
15 years at -25°C to +85°C

2FF, 3FF, 4FF

2FF, 3FF, MFF2

Network access: More networks for IoT projects

M2M SIMs can use a variety of mobile networks of different network operators both nationally and internationally (national roaming) and thus enable a connection for IoT and M2M projects almost everywhere. Conventional SIM cards usually only use the network of the SIM-issuing network operator, i.e. the provider with whom the mobile phone contract was concluded, especially in Germany. However, the availability of this one network varies depending on the location: sometimes there is good reception, sometimes there is none at all.

In order to avoid disconnections as much as possible in IoT and M2M projects, M2M SIM cards can also use the networks of different network operators (in Germany Telekom, Vodafone and O2) within Germany. M2M SIM cards are therefore also called multi-network SIMs or roaming SIMs.

But even with M2M SIM cards there are differences in network access: SIMs from independent companies, such as the wherever SIM, do not prefer any mobile network and thus allow the device to connect to the best possible network at the location. In this context, one also speaks of network independence or uncontrolled roaming. The M2M SIMs of the major network operators usually prioritise their own network. So before a terminal device is allowed to connect to the network of another mobile network operator, its own network must no longer be available. Until then, the device - no matter how poor the reception - always remains in the network of one network operator. This prioritisation of networks can be a disadvantage, especially for projects in which a strong and reliable connection is permanently required.

SIM management and monitoring via platform

M2M SIM cards are connected to a platform for easier management. This is used to configure both the SIM cards and the associated endpoints. For example, service profiles can be set up for M2M SIMs, SIM cards can be activated and deactivated or mobile networks can be excluded for use(blacklisting).

In addition, comprehensive monitoring is possible via such portals. Users can see the status of the end device, whether and to which network the SIM card is connected and how much data it transmits. In the event of a problem, various diagnostic functions such as a remote reset of the SIM card can help.

At wherever SIM, we offer a clear online portal and a comprehensive API for easier management of M2M SIM cards, which can be used to transfer data from the wherever SIM portal to your own systems.

Monitoring and surveillance

In addition to technical performance, the online portal is an important tool for monitoring SIM cards against misuse, improper use or unexpectedly high costs.

Cost control can be carried out via various configuration options. The configuration of permitted networks and countries ensures that end devices only connect according to the booked tariffs. Additional data limits and notifications prevent overconsumption or overuse of data or at least provide information in time to make further decisions. However, once a data limit is set and reached, the device cannot transfer any more data unless the limit is suspended. For some use cases, this is not an option, as a permanent connection of the device is necessary. In these cases, data pools are often used: The possible additional consumption of an M2M SIM is compensated by the lower consumption of other SIMs in the pool.

The misuse and misappropriation of the SIM card can be prevented by IMEI lock. This function prohibits the use of the SIM in a terminal other than the one assigned to it in the portal. This binding can only be removed via the portal. So if a SIM with IMEI lock is stolen from a device, this M2M SIM is useless in other terminals.

Safety and reliability

Security is essential for M2M communication. That is why mobile network providers already separate M2M connections from the rest of the data traffic in their core network. This is made possible by so-called APNs. These are private access points to the network. This APN must be entered once for the SIM so that it can enable the connection to the network at all. If the data traffic between the end device and the system is to be additionally protected, VPNs can also be used.

M2M tariffs and billing models

Unlike conventional data tariffs, M2M tariffs must cover a significantly larger bandwidth: The fluctuations in data requirements are only a few kilobytes or several gigabytes, depending on the application. For this reason, there are a variety of different tariff offers and billing models especially for M2M projects.

For example, the already mentioned data pooling. In this constellation, all active M2M SIMs use a joint data quota in which a lower consumption of SIM cards compensates for a higher data consumption of individual SIMs.