Home Postcode finder SA Blanche Harbor Blanche Harbor postcode SA Blanche Harbor is a locality in South Australia covered by postcode 5700. Postcode 5700 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Blanche Harbor business listing Be the first listing in Blanche Harbor Common questionsWhat is the postcode for Blanche Harbor?Blanche Harbor, SA has the postcode 5700.What state is Blanche Harbor in?Blanche Harbor is in South Australia (SA).Does postcode 5700 cover more than one suburb?Yes. Postcode 5700 covers 8 localities, so the postcode alone does not identify Blanche Harbor. Browse other postcodes in South Australia, or widen the search to every Australian postcode.