Home Postcodes by state WA 6023 Postcode 6023 6023 is the postcode for Duncraig, WA. Localities with postcode 6023DuncraigWA Postcode 6023 State or territory Western Australia (WA) Localities 1 Council area Joondalup Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6022 · Postcode 6024