Systems (100) and methods (400) for Radio Frequency Identification (“RFID”) security tags. The methods comprise: concurrently reading the RFID security tags and locator tags to obtain unique identifiers thereof and Received Signal Strength Indicator (“RSSI”) measurements therefore, where the RFID security tags are respectively coupled to inventory items located within a facility and the locator tags are placed at locations within the facility so as to respectively define a plurality of Zones Of Interest (“ZOIs”) in which inventory items may reside; and determining which ZOI of the plurality of ZOIs each said RFID security tag resides within based at least on the RSSI measurements, a number of times each locator tag was read, read times specifying when the locator tags were read, differences in read times for the locator tags, and known locations of the locator tags.