Home Postcode finder SA Marion Bay Marion Bay postcode SA Marion Bay is a locality in South Australia covered by postcode 5575. Postcode 5575 State or territory South Australia (SA) Region Sa Subs Near 1 Add a free Marion Bay business listing Be the first listing in Marion Bay Common questionsWhat is the postcode for Marion Bay?Marion Bay, SA has the postcode 5575.What state is Marion Bay in?Marion Bay is in South Australia (SA).Does postcode 5575 cover more than one suburb?Yes. Postcode 5575 covers 17 localities, so the postcode alone does not identify Marion Bay. Browse other postcodes in South Australia, or widen the search to every Australian postcode.