Home Postcode finder SA Mount Joy Mount Joy postcode SA Mount Joy is a locality in South Australia covered by postcode 5670. Postcode 5670 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Mount Joy business listing Be the first listing in Mount Joy Common questionsWhat is the postcode for Mount Joy?Mount Joy, SA has the postcode 5670.What state is Mount Joy in?Mount Joy is in South Australia (SA).Does postcode 5670 cover more than one suburb?Yes. Postcode 5670 covers 11 localities, so the postcode alone does not identify Mount Joy. Browse other postcodes in South Australia, or widen the search to every Australian postcode.