Home Postcode finder SA Morphetts Flat Morphetts Flat postcode SA Morphetts Flat is a locality in South Australia covered by postcode 5320. Postcode 5320 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Morphetts Flat business listing Be the first listing in Morphetts Flat Common questionsWhat is the postcode for Morphetts Flat?Morphetts Flat, SA has the postcode 5320.What state is Morphetts Flat in?Morphetts Flat is in South Australia (SA).Does postcode 5320 cover more than one suburb?Yes. Postcode 5320 covers 13 localities, so the postcode alone does not identify Morphetts Flat. Browse other postcodes in South Australia, or widen the search to every Australian postcode.