Home Postcode finder SA Seal Bay Seal Bay postcode SA Seal Bay is a locality in South Australia covered by postcode 5223. Postcode 5223 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Seal Bay business listing Be the first listing in Seal Bay Common questionsWhat is the postcode for Seal Bay?Seal Bay, SA has the postcode 5223.What state is Seal Bay in?Seal Bay is in South Australia (SA).Does postcode 5223 cover more than one suburb?Yes. Postcode 5223 covers 30 localities, so the postcode alone does not identify Seal Bay. Browse other postcodes in South Australia, or widen the search to every Australian postcode.