Home Postcode finder QLD Grassdale Grassdale postcode QLD Grassdale is a locality in Queensland covered by postcode 4405. Postcode 4405 State or territory Queensland (QLD) Region Toowoomba Region Add a free Grassdale business listing Be the first listing in Grassdale Common questionsWhat is the postcode for Grassdale?Grassdale, QLD has the postcode 4405.What state is Grassdale in?Grassdale is in Queensland (QLD).Does postcode 4405 cover more than one suburb?Yes. Postcode 4405 covers 11 localities, so the postcode alone does not identify Grassdale. Browse other postcodes in Queensland, or widen the search to every Australian postcode.