All the 5 regular teams that had been participating in the tournament for the previous several editions, took part under the South Zone in the Ranji Trophy, 1979-80, as well. The teams were selected from the Southern region of India and they included the likes of Andhra, Hyderabad, Kerala, Karnataka and Tamil Nadu. All the teams had the same aim of becoming one of the top two teams in the zone and also getting a chance in the knock out level of the tournament. However, only the teams like Hyderabad and Tamil Nadu eventually became successful to achieve this aim and entered into the knock out level from the South Zone.

The teams of Kerala and Andhra appeared in the first of the South Zone league matches in the Ranji Trophy, 1979-80 and they played the match at Quilon from 03-05 November, 1979. It was a drawn match and it saw the Kerala and Andhra teams earning 5 and 3 points, respectively from it. The Andhra team appeared in the second match of the zone also and this time, it played against the Hyderabad team at Nizamabad from 10-12 November, 1979. The Hyderabad team played wonderfully in the match and clinched a huge victory of 10 wickets for earning 8 valuable points from it. The next match saw a battle between the teams of Karnataka and Kerala at Shimoga from 10-12 November, 1979. The drawn match saw the Karnataka team earning 6 points and Kerala earning 3 points from it.

The match between the teams of Andhra and Tamil Nadu was the fourth of the South Zone league matches in the Ranji Trophy, 1979-80. The teams played the match at Guntur from 16-18 November, 1979 and the Andhra and Tamil Nadu teams earned 2 points, each from the drawn match. The Tamil Nadu team then clashed with the Karnataka team in the next match of the zone and the match took place at Bangalore from 30 November-02 December, 1979. This was another drawn match in the zone and it earned the Karnataka and Tamil Nadu teams 5 and 3 points, respectively. The Tamil Nadu team appeared in the next match of the zone also and this time, it played against the Kerala team at Madras from 13-15 December, 1979. The winner of the match was the Tamil Nadu team with a margin of an innings and 31 runs and the team earned the entire 9 points from the match, as well.

The clash between the teams of Hyderabad and Karnataka took place in the next match of the zone and the match was held at Hyderabad from 13-15 December, 1979. The Karnataka and Hyderabad teams earned 5 and 3 points, respectively from the match, as it remained drawn during the stipulated duration. The eighth of the South Zone league matches in the Ranji Trophy, 1979-80 involved the teams like Tamil Nadu and Hyderabad and the match was held at Madras from 26-28 December, 1979. The Hyderabad and Tamil Nadu teams earned 5 and 3 points, respectively from the drawn match. The teams of Andhra and Karnataka clashed with each other in the next match of the zone that was played at Vijayawada from 27-29 December, 1979. This was another drawn match in the zone that saw the Karnataka and Andhra teams earning 5 and 3 points, respectively from it. The last of the South Zone league matches in the Ranji Trophy, 1979-80 was played between the teams of Kerala and Hyderabad at Palghat from 30 December, 1979 - 01 January, 1980. The Hyderabad team played very well in the match and earned the entire 9 points from it, by clinching a victory of an innings and 52 runs.