Home Postcode finder SA Mount Gambier East Mount Gambier East postcode SA Mount Gambier East is a locality in South Australia covered by postcode 5291. Postcode 5291 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Mount Gambier East business listing Be the first listing in Mount Gambier East Common questionsWhat is the postcode for Mount Gambier East?Mount Gambier East, SA has the postcode 5291.What state is Mount Gambier East in?Mount Gambier East is in South Australia (SA).Does postcode 5291 cover more than one suburb?Yes. Postcode 5291 covers 34 localities, so the postcode alone does not identify Mount Gambier East. Browse other postcodes in South Australia, or widen the search to every Australian postcode.