Home Postcode finder SA Lake Plains Lake Plains postcode SA Lake Plains is a locality in South Australia covered by postcode 5255. Postcode 5255 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Lake Plains business listing Be the first listing in Lake Plains Common questionsWhat is the postcode for Lake Plains?Lake Plains, SA has the postcode 5255.What state is Lake Plains in?Lake Plains is in South Australia (SA).Does postcode 5255 cover more than one suburb?Yes. Postcode 5255 covers 19 localities, so the postcode alone does not identify Lake Plains. Browse other postcodes in South Australia, or widen the search to every Australian postcode.