Home Postcode finder SA Rapid Bay Rapid Bay postcode SA Rapid Bay is a locality in South Australia covered by postcode 5204. Postcode 5204 State or territory South Australia (SA) Region Adelaide Add a free Rapid Bay business listing More business listings in Rapid Bay Businesses in Rapid BayRapid Bay Primary SchoolEssington Lewis Drive · 08 85984062 Common questionsWhat is the postcode for Rapid Bay?Rapid Bay, SA has the postcode 5204.What state is Rapid Bay in?Rapid Bay is in South Australia (SA).Does postcode 5204 cover more than one suburb?Yes. Postcode 5204 covers 10 localities, so the postcode alone does not identify Rapid Bay. Browse other postcodes in South Australia, or widen the search to every Australian postcode.