Home Postcode finder SA Wallaroo Plain Wallaroo Plain postcode SA Wallaroo Plain is a locality in South Australia covered by postcode 5556. Postcode 5556 State or territory South Australia (SA) Region Sa Subs Near 1 Add a free Wallaroo Plain business listing Be the first listing in Wallaroo Plain Common questionsWhat is the postcode for Wallaroo Plain?Wallaroo Plain, SA has the postcode 5556.What state is Wallaroo Plain in?Wallaroo Plain is in South Australia (SA).Does postcode 5556 cover more than one suburb?Yes. Postcode 5556 covers 4 localities, so the postcode alone does not identify Wallaroo Plain. Browse other postcodes in South Australia, or widen the search to every Australian postcode.