Home Postcode finder WA Thomson Brook Thomson Brook postcode WA Thomson Brook is a locality in Western Australia covered by postcode 6239. Postcode 6239 State or territory Western Australia (WA) Region Wa Subs 3 Sth Rd Add a free Thomson Brook business listing Be the first listing in Thomson Brook Common questionsWhat is the postcode for Thomson Brook?Thomson Brook, WA has the postcode 6239.What state is Thomson Brook in?Thomson Brook is in Western Australia (WA).Does postcode 6239 cover more than one suburb?Yes. Postcode 6239 covers 11 localities, so the postcode alone does not identify Thomson Brook. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.