Home Postcode finder NSW Downside Downside postcode NSW Downside is a locality in New South Wales covered by postcode 2650. Postcode 2650 State or territory New South Wales (NSW) Region Canberra Add a free Downside business listing Be the first listing in Downside Common questionsWhat is the postcode for Downside?Downside, NSW has the postcode 2650.What state is Downside in?Downside is in New South Wales (NSW).Does postcode 2650 cover more than one suburb?Yes. Postcode 2650 covers 52 localities, so the postcode alone does not identify Downside. Browse other postcodes in New South Wales, or widen the search to every Australian postcode.