Home Postcode finder WA Bannister Bannister postcode WA Bannister is a locality in Western Australia covered by postcode 6390. Postcode 6390 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Bannister business listing Be the first listing in Bannister Common questionsWhat is the postcode for Bannister?Bannister, WA has the postcode 6390.What state is Bannister in?Bannister is in Western Australia (WA).Does postcode 6390 cover more than one suburb?Yes. Postcode 6390 covers 11 localities, so the postcode alone does not identify Bannister. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.