Home Postcode finder WA Gascoyne River Gascoyne River postcode WA Gascoyne River is a locality in Western Australia covered by postcode 6705. Postcode 6705 State or territory Western Australia (WA) Region North West Suburbs Add a free Gascoyne River business listing Be the first listing in Gascoyne River Common questionsWhat is the postcode for Gascoyne River?Gascoyne River, WA has the postcode 6705.What state is Gascoyne River in?Gascoyne River is in Western Australia (WA).Does postcode 6705 cover more than one suburb?Yes. Postcode 6705 covers 4 localities, so the postcode alone does not identify Gascoyne River. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.