Power management techniques for a Subscriber Identity Module (SIM) of a wireless communication device (WCD) are described tat make use of a unique identifier for the SIM. In particu1ar a processor within the WCD reads a first unique identifier from the SIM when power is initially supplied to the WCD, and stores the first unique identifier within a computer-readable medium within the WCD. During a power management cycle, where power is terminated and then re-supplied to the SIM, the processor again receives a unique identifier from the SIM and compares the second unique identifier with the stored unique identifier. These tecbniques are useful in detecting whether the attached SIM has been exchanged for a different SIM while powered down during a power management cycle.