A security system may include a plurality of electronic devices, each having a unique identification (ID) associated therewith and configured to generate a temporary security code based upon the unique ID. The system may further include at least one mobile wireless communications device including a first Near-Field Communication (NFC) circuit, and a mobile controller configured to receive the temporary security code from a given electronic device from among the plurality of electronic devices. The system may also include an access control device associated with a personnel access position and including a second NFC sensor and a security controller. The security controller may be configured to receive the temporary security code from the first NFC sensor via NFC communications, selectively grant personnel access based upon the received temporary security code, and determine the unique ID associated with the given electronic device.