Home Postcodes by state WA 6448 Postcode 6448 6448 is the postcode for Gibson, WA. Localities with postcode 6448GibsonWA Postcode 6448 State or territory Western Australia (WA) Localities 1 Council area Esperance Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6447 · Postcode 6450