Home Postcodes by state SA 5401 Postcode 5401 5401 is the postcode for 3 localities in SA: Alma, Hamley Bridge and Salter Springs. Localities with postcode 5401AlmaSAHamley BridgeSASalter SpringsSA Postcode 5401 State or territory South Australia (SA) Localities 3 Council area Mainly Wakefield, partly Clare and Gilbert Valleys; Wakefield Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5400 · Postcode 5410