Up to now, IoT has always had to use standard plastic SIMs, but eSIM is changing all that with the potential for increased openness and flexibility. The original SIM card – the plastic card inserted into your mobile phone to determine which network operator (MNO) your phone is assigned to – has essentially not changed much since it first came to the market in 1991. It has been well suited to the sales process in specialist mobile retail stores, where the SIM is inserted into the phone at the point of sale. The situation for connected devices in the M2M (machine to machine) market, and then IoT, has always been entirely different. These devices, such as asset trackers, cars, CCTV cameras, healthcare devices, security alarms and smart meters, are usually shipped direct to where they will be used and the plastic SIM cards then have to be matched up with them on site. This has always been logistically challenging but has become increasingly untenable as the volumes of manufactured devices requiring to be connected have risen sharply in recent years. A particular case in point is auto manufacture, but many others as well. eSIM provides the way forward for this, a solution where unassigned SIM components (called eUICCs – embedded Universal Integrated Circuit Cards) can be built into devices during manufacture and then updated with the most appropriate MNO profile Over the Air (OTA) when they are switched on in the field. Using cloud-based services, this allows them to automatically find the local MNO assigned to their contract, establish the connection and start sending back data from the device. It also means that the assigned MNO can now be changed remotely, for example at a contract renewal, without having to resort to changing out physical SIM cards in all devices wherever they happen to be.