2018 Pan Pacific Swimming Championships – Women's 4 × 100 metre medley relay
# 2018 Pan Pacific Swimming Championships – Women's 4 × 100 metre medley relay

The women's 4 × 100 metre medley relay competition at the 2018 Pan Pacific Swimming Championships took place on August 12 at the Tokyo Tatsumi International Swimming Center. The defending champion was Australia.

## Records

Prior to this competition, the existing world and Pan Pacific records were as follows:

| World record | United States (USA) Kathleen Baker (58.54) Lilly King (1:04.48) Kelsi Worrell (56.30) Simone Manuel (52.23) | 3:51.55 | Budapest, Hungary | 30 July 2017 |
| - | - | - | - | - |
| Pan Pacific Championships record | United States (USA) Natalie Coughlin (59.85) Rebecca Soni (1:05.35) Dana Vollmer (56.91) Jessica Hardy (53.12) | 3:55.23 | Irvine, United States | 21 August 2010 |

## Results

All times are in minutes and seconds.

| KEY: | CR | Championships record | NR | National record | PB | Personal best | SB | Seasonal best |
| - | - | - | - | - | - | - | - | - |

### Final

The final was held on 12 August from 18:00.

| Rank | Lane | Nation | Swimmers | Time | Notes |
| - | - | - | - | - | - |
| | 5 | Australia | Emily Seebohm (59.28) Jessica Hansen (1:05.82) Emma McKeon (56.45) Cate Campbell (51.19) | 3:52.74 | CR |
| | 4 | United States | Kathleen Baker (59.41) Lilly King (1:04.86) Kelsi Dahlia (56.72) Simone Manuel (52.22) | 3:53.21 | |
| | 3 | Japan | Natsumi Sakai (59.20) Reona Aoki (1:06.84) Rikako Ikee (55.48) Tomomi Aoki (53.51) | 3:55.03 | NR |
| 4 | 6 | Canada | Kylie Masse (58.63) Kelsey Wog (1:07.28) Rebecca Smith (57.51) Taylor Ruck (51.72) | 3:55.14 | |
| 5 | 2 | Philippines | Chloe Isleta (1:04.22) Miranda Renner (1:14.90) Rosalee Santa Ana (1:06.42) Nicole Oliva (56.64) | 4:22.18 | |
