Home Postcode finder SA Willson River Willson River postcode SA Willson River is a locality in South Australia covered by postcode 5222. Postcode 5222 State or territory South Australia (SA) Region Sa Subs Near 2 Add a free Willson River business listing Be the first listing in Willson River Common questionsWhat is the postcode for Willson River?Willson River, SA has the postcode 5222.What state is Willson River in?Willson River is in South Australia (SA).Does postcode 5222 cover more than one suburb?Yes. Postcode 5222 covers 17 localities, so the postcode alone does not identify Willson River. Browse other postcodes in South Australia, or widen the search to every Australian postcode.