Home Postcode finder SA Coonamia Coonamia postcode SA Coonamia is a locality in South Australia covered by postcode 5540. Postcode 5540 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Coonamia business listing Be the first listing in Coonamia Common questionsWhat is the postcode for Coonamia?Coonamia, SA has the postcode 5540.What state is Coonamia in?Coonamia is in South Australia (SA).Does postcode 5540 cover more than one suburb?Yes. Postcode 5540 covers 14 localities, so the postcode alone does not identify Coonamia. Browse other postcodes in South Australia, or widen the search to every Australian postcode.