Home Postcode finder SA Caroline Caroline postcode SA Caroline is a locality in South Australia covered by postcode 5291. Postcode 5291 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Caroline business listing Be the first listing in Caroline Common questionsWhat is the postcode for Caroline?Caroline, SA has the postcode 5291.What state is Caroline in?Caroline is in South Australia (SA).Does postcode 5291 cover more than one suburb?Yes. Postcode 5291 covers 34 localities, so the postcode alone does not identify Caroline. Browse other postcodes in South Australia, or widen the search to every Australian postcode.