Home Postcodes by state WA 6503 Postcode 6503 6503 is the postcode for 20 localities in WA: Bambun, Beermullah, Boonanarring, Breera, Coonabidgee, Cowalla and 14 more. Localities with postcode 6503BambunWABeermullahWABoonanarringWABreeraWACoonabidgeeWACowallaWACullallaWAGinginWAGinginupWAGranvilleWALennard BrookWAMindarraWAMoondahWAMoore River National ParkWAMuckenburraWANeergabbyWAOrange SpringsWARed GullyWAWanerieWAYealWA Postcode 6503 State or territory Western Australia (WA) Localities 20 Council area Gingin Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6502 · Postcode 6504