Home Postcode finder VIC Gateway Island Gateway Island postcode VIC Gateway Island is a locality in Victoria covered by postcode 3691. Postcode 3691 State or territory Victoria (VIC) Region Vic Far Country Add a free Gateway Island business listing Be the first listing in Gateway Island Common questionsWhat is the postcode for Gateway Island?Gateway Island, VIC has the postcode 3691.What state is Gateway Island in?Gateway Island is in Victoria (VIC).Does postcode 3691 cover more than one suburb?Yes. Postcode 3691 covers 34 localities, so the postcode alone does not identify Gateway Island. It also appears in 2 states or territories, so it does not identify a state either. Browse other postcodes in Victoria, or widen the search to every Australian postcode.