Home Postcodes by state VIC 3781 Postcode 3781 3781 is the postcode for 3 localities in VIC: Cockatoo, Mount Burnett and Nangana. Localities with postcode 3781CockatooVICMount BurnettVICNanganaVIC Postcode 3781 State or territory Victoria (VIC) Localities 3 Council area Cardinia Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 3779 · Postcode 3782