Home Postcode finder SA Jamestown Jamestown postcode SA Jamestown is a locality in South Australia covered by postcode 5491. Postcode 5491 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Jamestown business listing More business listings in Jamestown Businesses in JamestownJamestown Community School1 Humphris Terrace · 08 86642700Redden Bros Pty Ltd15 OD 5 Road · 08 8664 0660St James' School1 King Edward Terrace · 08 86641120 Common questionsWhat is the postcode for Jamestown?Jamestown, SA has the postcode 5491.What state is Jamestown in?Jamestown is in South Australia (SA).Does postcode 5491 cover more than one suburb?Yes. Postcode 5491 covers 7 localities, so the postcode alone does not identify Jamestown. Browse other postcodes in South Australia, or widen the search to every Australian postcode.