Home Postcode finder SA Mayfield Mayfield postcode SA Mayfield is a locality in South Australia covered by postcode 5454. Postcode 5454 State or territory South Australia (SA) Region Sa Subs Near 1 Add a free Mayfield business listing Be the first listing in Mayfield Common questionsWhat is the postcode for Mayfield?Mayfield, SA has the postcode 5454.What state is Mayfield in?Mayfield is in South Australia (SA).Does postcode 5454 cover more than one suburb?Yes. Postcode 5454 covers 7 localities, so the postcode alone does not identify Mayfield. Browse other postcodes in South Australia, or widen the search to every Australian postcode.