The Women's 4x100 Freestyle Relay swimming event at the 2009 SEA Games was held on December 11, 2009. Of note, in the event's final, the top-3 teams all swam faster than the then-Games Record in the event.
Results edit
Final edit
| Place | Lane | Nation | Swimmers | Time | Notes |
|---|---|---|---|---|---|
| 1 | 4 |  Singapore |
Lynette Lim Amanda Lim Mylene Ong Quah Ting Wen |
3:45.73 | GR |
| 2 | 7 |  Thailand |
3:48.09 | ||
| 3 | 5 |  Malaysia |
3:51.40 | ||
| 4 | 6 |  Philippines |
3:56.20 | ||
| 5 | 3 |  Indonesia |
3:59.75 | ||
| 6 | 2 |  Laos |
5:12.91 |