Home Postcodes by state SA 5049 Postcode 5049 5049 is the postcode for 5 localities in SA: Kingston Park, Marino, Seacliff, Seacliff Park and Seaview Downs. Localities with postcode 5049Kingston ParkSAMarinoSASeacliffSASeacliff ParkSASeaview DownsSA Postcode 5049 State or territory South Australia (SA) Localities 5 Council area Holdfast Bay; Marion; Mainly Holdfast Bay, partly Marion Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5048 · Postcode 5050