Home Postcode finder SA Dawson Dawson postcode SA Dawson is a locality in South Australia covered by postcode 5422. Postcode 5422 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Dawson business listing Be the first listing in Dawson Common questionsWhat is the postcode for Dawson?Dawson, SA has the postcode 5422.What state is Dawson in?Dawson is in South Australia (SA).Does postcode 5422 cover more than one suburb?Yes. Postcode 5422 covers 13 localities, so the postcode alone does not identify Dawson. Browse other postcodes in South Australia, or widen the search to every Australian postcode.