Home Postcode finder SA Outer Harbor Outer Harbor postcode SA Outer Harbor is a locality in South Australia covered by postcode 5018. Postcode 5018 State or territory South Australia (SA) Region Adelaide Add a free Outer Harbor business listing Be the first listing in Outer Harbor Common questionsWhat is the postcode for Outer Harbor?Outer Harbor, SA has the postcode 5018.What state is Outer Harbor in?Outer Harbor is in South Australia (SA).Does postcode 5018 cover more than one suburb?Yes. Postcode 5018 covers 2 localities, so the postcode alone does not identify Outer Harbor. Browse other postcodes in South Australia, or widen the search to every Australian postcode.