Home Postcode finder SA Boston Boston postcode SA Boston is a locality in South Australia covered by postcode 5607. Postcode 5607 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Boston business listing Be the first listing in Boston Common questionsWhat is the postcode for Boston?Boston, SA has the postcode 5607.What state is Boston in?Boston is in South Australia (SA).Does postcode 5607 cover more than one suburb?Yes. Postcode 5607 covers 50 localities, so the postcode alone does not identify Boston. Browse other postcodes in South Australia, or widen the search to every Australian postcode.