Home Postcode finder SA Lock Lock postcode SA Lock is a locality in South Australia covered by postcode 5633. Postcode 5633 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Lock business listing More business listings in Lock Businesses in LockLock Area SchoolWest Terrace · 08 86891019 Common questionsWhat is the postcode for Lock?Lock, SA has the postcode 5633.What state is Lock in?Lock is in South Australia (SA).Does postcode 5633 cover more than one suburb?Yes. Postcode 5633 covers 2 localities, so the postcode alone does not identify Lock. Browse other postcodes in South Australia, or widen the search to every Australian postcode.