Home Postcodes by state WA 6620 Postcode 6620 6620 is the postcode for 2 localities in WA: Perenjori and Rothsay. Localities with postcode 6620PerenjoriWARothsayWA Postcode 6620 State or territory Western Australia (WA) Localities 2 Council area Perenjori Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 6616 · Postcode 6623