Home Postcode finder WA Cardiff Cardiff postcode WA Cardiff is a locality in Western Australia covered by postcode 6225. Postcode 6225 State or territory Western Australia (WA) Region Wa Subs 3 Sth Rd Add a free Cardiff business listing Be the first listing in Cardiff Common questionsWhat is the postcode for Cardiff?Cardiff, WA has the postcode 6225.What state is Cardiff in?Cardiff is in Western Australia (WA).Does postcode 6225 cover more than one suburb?Yes. Postcode 6225 covers 18 localities, so the postcode alone does not identify Cardiff. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.