A multi-IMSI SIM card is exactly what it sounds like; a SIM card with multiple SIM profiles and therefore multiple IMSI numbers. Having multiple SIM profiles makes it easier for businesses to switch between carriers, which allows for a better connection and improved up-time as your devices migrate to another network when your signal drops.
For example, businesses with fleets of lorries or vans want to keep track of their vehicles at all times. By deploying single-IMSI M2M SIM cards, their trackers would only be able to connect to one specific network carrier. When these vehicles enter a remote location with limited network coverage or cross a border into another country, there is a good chance that the tracker will lose connection to the network. By replacing these SIM cards with multi-IMSI M2M SIM cards, these fleet trackers are able to connect to another carrier when their connection is poor or lost, decreasing the likelihood of any downtime.
Multi-IMSI solutions provide businesses with a lot more flexibility since they can maintain a connection with the mobile network carriers at all times. It also means that they can utilise local networks and not be subjected to pricey roaming charges when operating abroad.