Home Postcode finder WA Mount Wells Mount Wells postcode WA Mount Wells is a locality in Western Australia covered by postcode 6390. Postcode 6390 State or territory Western Australia (WA) Region Wa Subs 2 Gsr Add a free Mount Wells business listing Be the first listing in Mount Wells Common questionsWhat is the postcode for Mount Wells?Mount Wells, WA has the postcode 6390.What state is Mount Wells in?Mount Wells is in Western Australia (WA).Does postcode 6390 cover more than one suburb?Yes. Postcode 6390 covers 11 localities, so the postcode alone does not identify Mount Wells. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.