Home Postcode finder WA Hillside Hillside postcode WA Hillside is a locality in Western Australia covered by postcode 6312. Postcode 6312 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Hillside business listing Be the first listing in Hillside Common questionsWhat is the postcode for Hillside?Hillside, WA has the postcode 6312.What state is Hillside in?Hillside is in Western Australia (WA).Does postcode 6312 cover more than one suburb?Yes. Postcode 6312 covers 9 localities, so the postcode alone does not identify Hillside. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.