Home Postcode finder TAS Osmaston Osmaston postcode TAS Osmaston is a locality in Tasmania covered by postcode 7303. Postcode 7303 State or territory Tasmania (TAS) Region Tasmania Add a free Osmaston business listing Be the first listing in Osmaston Common questionsWhat is the postcode for Osmaston?Osmaston, TAS has the postcode 7303.What state is Osmaston in?Osmaston is in Tasmania (TAS).Does postcode 7303 cover more than one suburb?Yes. Postcode 7303 covers 7 localities, so the postcode alone does not identify Osmaston. Browse other postcodes in Tasmania, or widen the search to every Australian postcode.