Home Postcode finder SA Inkster Inkster postcode SA Inkster is a locality in South Australia covered by postcode 5680. Postcode 5680 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Inkster business listing Be the first listing in Inkster Common questionsWhat is the postcode for Inkster?Inkster, SA has the postcode 5680.What state is Inkster in?Inkster is in South Australia (SA).Does postcode 5680 cover more than one suburb?Yes. Postcode 5680 covers 20 localities, so the postcode alone does not identify Inkster. Browse other postcodes in South Australia, or widen the search to every Australian postcode.