Home Postcodes by state WA 6042 Postcode 6042 6042 is the postcode for Seabird, WA. Localities with postcode 6042SeabirdWA Postcode 6042 State or territory Western Australia (WA) Localities 1 Council area Gingin Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6041 · Postcode 6043