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:

Results
All times are in minutes and seconds.

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