Home Postcodes by state WA 6174 Postcode 6174 6174 is the postcode for Golden Bay, WA. Localities with postcode 6174Golden BayWA Postcode 6174 State or territory Western Australia (WA) Localities 1 Council area Rockingham Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6173 · Postcode 6175