Home Postcode finder WA Koolyanobbing Koolyanobbing postcode WA Koolyanobbing is a locality in Western Australia covered by postcode 6427. Postcode 6427 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Koolyanobbing business listing Be the first listing in Koolyanobbing Common questionsWhat is the postcode for Koolyanobbing?Koolyanobbing, WA has the postcode 6427.What state is Koolyanobbing in?Koolyanobbing is in Western Australia (WA).Does postcode 6427 cover more than one suburb?No. Postcode 6427 covers Koolyanobbing only, which is unusual - most Australian postcodes cover several localities. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.