Home Postcode finder WA Koolanooka Koolanooka postcode WA Koolanooka is a locality in Western Australia covered by postcode 6623. Postcode 6623 State or territory Western Australia (WA) Region Wa Subs 4 Coast Add a free Koolanooka business listing Be the first listing in Koolanooka Common questionsWhat is the postcode for Koolanooka?Koolanooka, WA has the postcode 6623.What state is Koolanooka in?Koolanooka is in Western Australia (WA).Does postcode 6623 cover more than one suburb?Yes. Postcode 6623 covers 6 localities, so the postcode alone does not identify Koolanooka. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.