Home Postcode finder WA Howick Howick postcode WA Howick is a locality in Western Australia covered by postcode 6450. Postcode 6450 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Howick business listing Be the first listing in Howick Common questionsWhat is the postcode for Howick?Howick, WA has the postcode 6450.What state is Howick in?Howick is in Western Australia (WA).Does postcode 6450 cover more than one suburb?Yes. Postcode 6450 covers 23 localities, so the postcode alone does not identify Howick. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.