Home Postcodes by state WA 6020 Postcode 6020 6020 is the postcode for 5 localities in WA: Carine, Marmion, North Beach, Sorrento and Watermans Bay. Localities with postcode 6020CarineWAMarmionWANorth BeachWASorrentoWAWatermans BayWA Postcode 6020 State or territory Western Australia (WA) Localities 5 Council area Stirling; Joondalup Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6019 · Postcode 6021