Home Postcode finder SA Wattle Flat Wattle Flat postcode SA Wattle Flat is a locality in South Australia covered by postcode 5203. Postcode 5203 State or territory South Australia (SA) Region Adelaide Add a free Wattle Flat business listing Be the first listing in Wattle Flat Common questionsWhat is the postcode for Wattle Flat?Wattle Flat, SA has the postcode 5203.What state is Wattle Flat in?Wattle Flat is in South Australia (SA).Does postcode 5203 cover more than one suburb?Yes. Postcode 5203 covers 6 localities, so the postcode alone does not identify Wattle Flat. Browse other postcodes in South Australia, or widen the search to every Australian postcode.