Home Postcodes by state VIC 3089 Postcode 3089 3089 is the postcode for Diamond Creek, VIC. Localities with postcode 3089Diamond CreekVIC Postcode 3089 State or territory Victoria (VIC) Localities 1 Council area Nillumbik Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3088 · Postcode 3090