Home Postcode finder SA Wellington Wellington postcode SA Wellington is a locality in South Australia covered by postcode 5259. Postcode 5259 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Wellington business listing Be the first listing in Wellington Common questionsWhat is the postcode for Wellington?Wellington, SA has the postcode 5259.What state is Wellington in?Wellington is in South Australia (SA).Does postcode 5259 cover more than one suburb?Yes. Postcode 5259 covers 12 localities, so the postcode alone does not identify Wellington. Browse other postcodes in South Australia, or widen the search to every Australian postcode.