Home Postcode finder SA Cockburn Cockburn postcode SA Cockburn is a locality in South Australia covered by postcode 5440. Postcode 5440 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Cockburn business listing Be the first listing in Cockburn Common questionsWhat is the postcode for Cockburn?Cockburn, SA has the postcode 5440.What state is Cockburn in?Cockburn is in South Australia (SA).Does postcode 5440 cover more than one suburb?Yes. Postcode 5440 covers 7 localities, so the postcode alone does not identify Cockburn. Browse other postcodes in South Australia, or widen the search to every Australian postcode.