Home Postcode finder WA Rothsay Rothsay postcode WA Rothsay is a locality in Western Australia covered by postcode 6620. Postcode 6620 State or territory Western Australia (WA) Region Wa Subs 4 Coast Add a free Rothsay business listing Be the first listing in Rothsay Common questionsWhat is the postcode for Rothsay?Rothsay, WA has the postcode 6620.What state is Rothsay in?Rothsay is in Western Australia (WA).Does postcode 6620 cover more than one suburb?Yes. Postcode 6620 covers 2 localities, so the postcode alone does not identify Rothsay. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.