Home Postcode finder SA Barna Barna postcode SA Barna is a locality in South Australia covered by postcode 5641. Postcode 5641 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Barna business listing Be the first listing in Barna Common questionsWhat is the postcode for Barna?Barna, SA has the postcode 5641.What state is Barna in?Barna is in South Australia (SA).Does postcode 5641 cover more than one suburb?Yes. Postcode 5641 covers 13 localities, so the postcode alone does not identify Barna. Browse other postcodes in South Australia, or widen the search to every Australian postcode.