Home Postcode finder SA Long Flat Long Flat postcode SA Long Flat is a locality in South Australia covered by postcode 5253. Postcode 5253 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Long Flat business listing Be the first listing in Long Flat Common questionsWhat is the postcode for Long Flat?Long Flat, SA has the postcode 5253.What state is Long Flat in?Long Flat is in South Australia (SA).Does postcode 5253 cover more than one suburb?Yes. Postcode 5253 covers 25 localities, so the postcode alone does not identify Long Flat. Browse other postcodes in South Australia, or widen the search to every Australian postcode.