| Women's 400 metre individual medley at the 2025 SEA Games | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Venue | SAT Swimming Pool | |||||||||
| Date | 13 December | |||||||||
| Competitors | 10 from 6 nations | |||||||||
| Winning time | 4:46.30 | |||||||||
| Medalists | ||||||||||
| ||||||||||
The women's 400 metre individual medley event at the 2025 SEA Games took place on 13 December 2025 at the SAT Swimming Pool in Bangkok, Thailand.
All times are Indochina Standard Time (UTC+07:00)
| Date | Time | Event |
|---|---|---|
| Saturday, 13 December 2025 | 9:38 | Heats |
| 19:25 | Final |
Prior to this competition, the existing world, Asian, and Southeast Asian Games records were as follows.
| World Record |  Summer McIntosh (CAN) | 4:23.65 | Victoria, Canada | 11 June 2025 |
| Asian Record |  Ye Shiwen (CHN) | 4:28.43 | London, United Kingdom | 28 July 2012 |
| Games Record |  Nguyễn Thị Ánh Viên (SGP) | 4:42.88 | Singapore, Singapore | 6 June 2015 |
| Rank | Heat | Lane | Swimmer | Nationality | Time | Notes |
|---|---|---|---|---|---|---|
| 1 | 2 | 4 | Kamonchanok Kwanmuang |  Thailand | 4:55.37 | Q |
| 2 | 1 | 5 | Victoria Carrie Lim Yiyan | Singapore | 5:00.38 | Q |
| 3 | 2 | 3 | Jinjutha Pholjamjumrus | Thailand | 5:00.50 | Q |
| 4 | 2 | 5 | Võ Thị Mỹ Tiên |  Vietnam | 5:04.50 | Q |
| 5 | 1 | 4 | Xiandi Chua |  Philippines | 5:05.09 | Q |
| 6 | 1 | 3 | Nguyễn Ngọc Tuyết Hân | Vietnam | 5:07.93 | Q |
| 7 | 2 | 2 | Kyla Louise Bulaga | Philippines | 5:11.84 | Q |
| 8 | 2 | 6 | Michelle Surjadi Fang |  Indonesia | 5:12.55 | Q |
| 9 | 1 | 2 | Jia Jia Yoong |  Malaysia | 5:20.43 | R |
| 10 | 1 | 6 | Shannon Tan Yan Qing | Malaysia | 5:20.52 | R |
| Rank | Lane | Swimmer | Nationality | Time | Notes |
|---|---|---|---|---|---|
 | 4 | Kamonchanok Kwanmuang | Thailand | 4:46.30 | |
 | 6 | Võ Thị Mỹ Tiên | Vietnam | 4:47.39 | |
 | 3 | Jinjutha Pholjamjumrus | Thailand | 4:47.62 | |
| 4 | 2 | Xiandi Chua | Philippines | 4:56.11 | |
| 5 | 5 | Victoria Carrie Lim Yiyan | Singapore | 4:56.51 | |
| 6 | 7 | Nguyễn Ngọc Tuyết Hân | Vietnam | 5:07.09 | |
| 7 | 1 | Kyla Louise Bulaga | Philippines | 5:08.52 | |
| 8 | 8 | Jia Jia Yoong | Malaysia | 5:20.84 |