Home Postcode finder WA Smith Brook Smith Brook postcode WA Smith Brook is a locality in Western Australia covered by postcode 6258. Postcode 6258 State or territory Western Australia (WA) Region Wa Subs 3 Sth Rd Add a free Smith Brook business listing Be the first listing in Smith Brook Common questionsWhat is the postcode for Smith Brook?Smith Brook, WA has the postcode 6258.What state is Smith Brook in?Smith Brook is in Western Australia (WA).Does postcode 6258 cover more than one suburb?Yes. Postcode 6258 covers 22 localities, so the postcode alone does not identify Smith Brook. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.