The Southern Districts Tennis Association senior summer competition season for 2020/21 consisted of 15 rounds with 100 teams competing each week.
Tennis SA and Southern Districts Tennis Association would like to thank the clubs and senior coordinators for their continued support and would like to formally congratulate the following winners:
Senior Competition
| Men | |
| Division 1 | Coromandel Valley |
| Division 2 | Denman |
| Division 3 | Kingswood |
| Division 4 | Hope Ward |
| Division 5 | Colonel Light West |
| Division 6 | Colonel Light West |
| Division 7 | Flagstaff Hill |
| Division 8 | Blackwood |
| Women | |
| Division 1 | Colonel Light West |
| Division 2 | O'Halloran Hill/McLaren Vale |
| Division 3 | Denman |
| Division 4 | Colonel Light West |
Mixed Doubles Competition
| Division 1 | Hackham |