A method for authenticating a circuit switched (CS) call on a virtual subscriber identity module (VSIM) includes: authenticating the VSIM for a packet switched (PS) call connection using authentication information obtained from a remote server through a software subscriber identity module (soft-SIM) connection to the remote server; initiating a call connection on a CS radio access technology (RAT) between the VSIM and a first communication network; and authenticating the VSIM CS call connection to the first communication network through the VSIM PS connection in response to an authentication request for the call connection on the CS RAT.