| Champ: |  Samantha Stosur |
| Runner: |  Victoria Azarenka |
| Score: | 6–2, 6–3 |
| Draw: | 28 |
| Seeds: | 8 |
| Type: | singles doubles |
| Before Name: | Mercury Insurance Open |
| After Name: | San Diego Open – Women's singles |
| After Year: | 2022 |
See main article: 2013 Southern California Open.
Dominika Cibulková was the defending champion, but lost in the first round to Ana Ivanovic.
Samantha Stosur won the title, defeating Victoria Azarenka in the final for the only time in her career with the score 6–2, 6–3.
The top four seeds receive a bye into the second round.