Home Postcode finder SA Collinsville Collinsville postcode SA Collinsville is a locality in South Australia covered by postcode 5418. Postcode 5418 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Collinsville business listing Be the first listing in Collinsville Common questionsWhat is the postcode for Collinsville?Collinsville, SA has the postcode 5418.What state is Collinsville in?Collinsville is in South Australia (SA).Does postcode 5418 cover more than one suburb?Yes. Postcode 5418 covers 2 localities, so the postcode alone does not identify Collinsville. Browse other postcodes in South Australia, or widen the search to every Australian postcode.