The compatibility of Subscriber Identity Module (SIM) cards between Android and iPhone devices hinges primarily on the SIM card size and the network technology utilized. A SIM card from an Android phone physically fits into an iPhone if both devices use the same SIM card size, such as a nano-SIM. Functionally, the SIM card stores information needed to connect to a cellular network. As an example, if an individual removes a nano-SIM from a Samsung Galaxy phone and inserts it into an iPhone 13, the iPhone, assuming it is unlocked, should be able to access the cellular network using the data stored on that SIM.
The interchangeability of SIM cards offers considerable convenience for users switching between devices. It allows for continued service without contacting a mobile carrier to activate a new SIM. Historically, differing SIM card sizes necessitated adapters or carrier intervention when changing phones. The move towards standardized nano-SIM cards has largely mitigated this issue, simplifying device transitions. This interoperability benefits users by enabling quick phone replacements or temporary use of different devices, retaining their existing phone number and mobile service.