| Event: | Women's 4 × 100 metre medley relay |
| Competition: | 2018 Pan Pacific Swimming Championships |
| Venue: | Tokyo Tatsumi International Swimming Center |
| Dates: | 12 August |
| Competitors: | 20 |
| Nations: | 5 |
| Win Value: | 3:52.74 |
| Gold: | Emily Seebohm Jessica Hansen Emma McKeon Cate Campbell |
| Goldnoc: | AUS |
| Silver: | Kathleen Baker Lilly King Kelsi Dahlia Simone Manuel |
| Silvernoc: | USA |
| Bronze: | Natsumi Sakai Reona Aoki Rikako Ikee Tomomi Aoki |
| Bronzenoc: | JPN |
| Prev: | 2014 |
| Next: | 2022 |
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.[1] The defending champion was Australia.[2]
Prior to this competition, the existing world and Pan Pacific records were as follows:
| World record | 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 | 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 |
All times are in minutes and seconds.
| KEY: | CR | Championships record | NR | National record | PB | Personal best | SB | Seasonal best |
The final was held on 12 August from 18:00.[3]
| Rank | Lane | Nation | Swimmers | Time | Notes | |
|---|---|---|---|---|---|---|
| 5 | Emily Seebohm (59.28) Jessica Hansen (1:05.82) Emma McKeon (56.45) Cate Campbell (51.19) | 3:52.74 | CR | |||
| 4 | Kathleen Baker (59.41) Lilly King (1:04.86) Kelsi Dahlia (56.72) Simone Manuel (52.22) | 3:53.21 | ||||
| 3 | Natsumi Sakai (59.20) Reona Aoki (1:06.84) Rikako Ikee (55.48) Tomomi Aoki (53.51) | 3:55.03 | NR | |||
| 4 | 6 | Kylie Masse (58.63) Kelsey Wog (1:07.28) Rebecca Smith (57.51) Taylor Ruck (51.72) | 3:55.14 | |||
| 5 | 2 | Chloe Isleta (1:04.22) Miranda Renner (1:14.90) Rosalee Santa Ana (1:06.42) Nicole Oliva (56.64) | 4:22.18 |