Home Postcode finder WA Boundain Boundain postcode WA Boundain is a locality in Western Australia covered by postcode 6312. Postcode 6312 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Boundain business listing Be the first listing in Boundain Common questionsWhat is the postcode for Boundain?Boundain, WA has the postcode 6312.What state is Boundain in?Boundain is in Western Australia (WA).Does postcode 6312 cover more than one suburb?Yes. Postcode 6312 covers 9 localities, so the postcode alone does not identify Boundain. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.