Home Postcode finder SA German Flat German Flat postcode SA German Flat is a locality in South Australia covered by postcode 5280. Postcode 5280 State or territory South Australia (SA) Region SA Outer Suburbs Add a free German Flat business listing Be the first listing in German Flat Common questionsWhat is the postcode for German Flat?German Flat, SA has the postcode 5280.What state is German Flat in?German Flat is in South Australia (SA).Does postcode 5280 cover more than one suburb?Yes. Postcode 5280 covers 16 localities, so the postcode alone does not identify German Flat. Browse other postcodes in South Australia, or widen the search to every Australian postcode.