Home Postcode finder SA Joanna Joanna postcode SA Joanna is a locality in South Australia covered by postcode 5271. Postcode 5271 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Joanna business listing Be the first listing in Joanna Common questionsWhat is the postcode for Joanna?Joanna, SA has the postcode 5271.What state is Joanna in?Joanna is in South Australia (SA).Does postcode 5271 cover more than one suburb?Yes. Postcode 5271 covers 18 localities, so the postcode alone does not identify Joanna. Browse other postcodes in South Australia, or widen the search to every Australian postcode.