Apparatus and methods to support parallel communication using multiple subscriber identities in a wireless communication device via multiple subscriber identity modules (SIMs) are disclosed. A representative method includes establishing a connection with a first wireless network via a first wireless cellular protocol software stack for a first subscriber identity associated with a first subscriber identity module; registering with a second wireless network via a second wireless cellular protocol software stack for a second subscriber identity associated with a second subscriber identity module; and receiving radio frequency signals from the second wireless network via the second wireless cellular protocol software stack in parallel with communicating with the first wireless network via the first wireless cellular protocol software stack. The first and second wireless cellular protocol software stacks share at least a portion of radio frequency wireless circuitry for communicating with the first and second wireless network respectively.