SES-8 Mt. Gambier started on 25 March 1966 and RTS-5a Riverland began 26 November 1976. SES was owned by South Australian media company South East Telecasters, and RTS by the subsidiary Riverland Television.

Current head of Channel Seven News Peter Meakin began his news directing career at SES-8 at the age of 24.

The stations were bought by WIN Television for $26.4 million in August 1999, which merged them and renamed them WIN South Australia. Win took a mix of programs from all 3 networks, Seven, Nine and Ten, with the majority from Nine.

Win was granted a supplementary TV licence under Section 38A of the Broadcasting Services Act in 2003, and began broadcasting a Network Ten affiliate, WIN Ten, in 2004. The original Win station then began broadcasting predominantly Nine Network material, with some Seven sport programming on occasion.