Home Postcodes by state WA 6638 Postcode 6638 6638 is the postcode for 4 localities in WA: Cooladar Hill, Daggar Hills, Mount Magnet and Paynesville. Localities with postcode 6638Cooladar HillWADaggar HillsWAMount MagnetWAPaynesvilleWA Postcode 6638 State or territory Western Australia (WA) Localities 4 Council area Mount Magnet Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6635 · Postcode 6639