The women's 4 × 100 metre medley relay competition at the 2010 Pan Pacific Swimming Championships took place on August 21 at the William Woollett Jr. Aquatics Center.

[1][2] The last champion was the United States.

[3][4] Prior to this competition, the existing world and Pan Pacific records were as follows: All times are in minutes and seconds.

Heats weren't performed, as only four teams had entered.

The final was held on August 21, at 20:15.