Home Postcodes by state SA 5164 Postcode 5164 5164 is the postcode for Christie Downs, SA. Localities with postcode 5164Christie DownsSA Postcode 5164 State or territory South Australia (SA) Localities 1 Council area Onkaparinga Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5163 · Postcode 5165