Home Postcodes by state WA 6018 Postcode 6018 6018 is the postcode for 6 localities in WA: Churchlands, Doubleview, Gwelup, Innaloo, Karrinyup and Woodlands. Localities with postcode 6018ChurchlandsWADoubleviewWAGwelupWAInnalooWAKarrinyupWAWoodlandsWA Postcode 6018 State or territory Western Australia (WA) Localities 6 Council area Stirling Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6017 · Postcode 6019