Home Postcodes by state SA 5089 Postcode 5089 5089 is the postcode for Highbury, SA. Localities with postcode 5089HighburySA Postcode 5089 State or territory South Australia (SA) Localities 1 Council area Tea Tree Gully Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5088 · Postcode 5090