Home Postcodes by state SA 5170 Postcode 5170 5170 is the postcode for Maslin Beach, SA. Localities with postcode 5170Maslin BeachSA Postcode 5170 State or territory South Australia (SA) Localities 1 Council area Onkaparinga Council area based on Australian Bureau of Statistics data (ASGS Edition 3), CC BY 4.0. Postcode 5169 · Postcode 5171