Home Postcodes by state VIC 3123 Postcode 3123 3123 is the postcode for 2 localities in VIC: Auburn and Hawthorn East. Localities with postcode 3123AuburnVICHawthorn EastVIC Postcode 3123 State or territory Victoria (VIC) Localities 2 Council area Boroondara Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3122 · Postcode 3124