Home Postcode finder WA South Boulder South Boulder postcode WA South Boulder is a locality in Western Australia covered by postcode 6432. Postcode 6432 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free South Boulder business listing Be the first listing in South Boulder Common questionsWhat is the postcode for South Boulder?South Boulder, WA has the postcode 6432.What state is South Boulder in?South Boulder is in Western Australia (WA).Does postcode 6432 cover more than one suburb?Yes. Postcode 6432 covers 4 localities, so the postcode alone does not identify South Boulder. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.