The women's 4 × 100 metre medley relay competition of the 2018 FINA World Swimming Championships (25 m) was held on 16 December 2018.

Records Prior to the competition, the existing world and championship records were as follows. Nation Time Location Date World record 3:45.20 Indianapolis, United States 11 December 2015 Championship record 3:47.89 Windsor, Canada 11 December 2016

Results Heats The heats were started at 10:20.Heats results

Rank Heat Lane Nation Swimmers Time Notes 1 2 5 Kathleen Baker (56.96)Melanie Margalis (1:04.85)Kendyl Stewart (56.29)Lia Neal (52.63) 3:50.73 Q 2 2 4 Fu Yuanhui (57.71)Shi Jinglin (1:05.07)Wang Yichun (56.26)Yang Junxuan (52.54) 3:51.58 Q 3 1 4 Minna Atherton (57.38)Jessica Hansen (1:05.28)Emily Seebohm (57.51)Ariarne Titmus (52.92) 3:53.09 Q 4 1 3 Margherita Panziera (57.63)Martina Carraro (1:05.32)Ilaria Bianchi (57.78)Federica Pellegrini (53.16) 3:53.89 Q 5 2 3 Emi Moronuki (57.44)Kanako Watanabe (1:06.52)Yukina Hirayama (57.81)Tomomi Aoki (53.31) 3:55.08 Q 6 1 5 Daria Ustinova (58.27)Vitalina Simonova (1:05.46)Daria Kartashova (57.61)Veronika Andrusenko (53.77) 3:55.11 Q 7 1 1 Laura Riedemann (58.40)Jessica Steiger (1:06.46)Aliena Schmidtke (58.52)Marie Pietruschka (53.92) 3:57.30 Q 8 2 2 Ingrid Wilm (58.55)Sophie Angus (1:06.46)Haley Black (56.49)Aela Janvier (55.97) 3:57.47 Q 9 1 6 Ekaterina Avramova (59.88) Viktoriya Zeynep Güneş (1:07.59)Nida Eliz Üstündağ (58.35)Selen Özbilen (54.66) 4:00.48 10 2 8 Seraina Sturzenegger (1:00.93)Lisa Mamie (1:06.79)Svenja Stoffel (58.47)Alexandra Touretski (54.47) 4:00.66 11 2 7 Karolina Hájková (59.76)Andrea Podmaníková (1:07.54)Tamara Potocká (59.67)Barbora Mikuskova (55.39) 4:02.36 12 2 1 Caroline Pilhatsch (59.49)Cornelia Pammer (1:07.84)Lena Kreundl (1:00.21)Marlene Kahler (55.29) 4:02.83 13 1 2 Emma Godwin (59.22) Ciara Smith (1:09.14)Vanessa Ouwehand (1:01.82)Paige Flynn (54.20) 4:04.38 14 2 6 Wong Toto Kwan To (1:00.09) Kan Cheuk Tung Natalie (1:10.17)Chan Kin Lok (1:00.70)Sze Hang Yu (55.07) 4:06.03 15 1 7 Chen Szu-an (1:03.67)Lin Pei-wun (1:10.85)Huang Mei-chien (1:02.93) Wang Wan-chen (58.32) 4:15.77

Final The final was held at 20:00.Final results

Rank Lane Nation Swimmers Time Notes 4 Olivia Smoliga (55.86)Katie Meili (1:03.52)Kelsi Dahlia (54.89)Mallory Comerford (51.31) 3:45.58 CR 5 Fu Yuanhui (56.86)Shi Jinglin (1:03.97)Zhang Yufei (56.21)Zhu Menghui (51.76) 3:48.80 6 Margherita Panziera (58.39)Martina Carraro (1:04.47)Elena Di Liddo (56.41)Federica Pellegrini (52.11) 3:51.38 4 2 Emi Moronuki (57.32)Kanako Watanabe (1:05.58)Ai Soma (56.27)Tomomi Aoki (52.64) 3:51.81 5 7 Anastasia Fesikova (57.73)Maria Temnikova (1:06.53)Svetlana Chimrova (56.90)Maria Kameneva (52.57) 3:53.73 6 1 Laura Riedemann (58.04)Jessica Steiger (1:05.80)Aliena Schmidtke (57.41)Annika Bruhn (52.90) 3:54.15 7 8 Ingrid Wilm (58.63)Sophie Angus (1:06.23)Haley Black (57.08)Aela Janvier (56.10) 3:58.04 3 Minna Atherton (56.91)Jessica Hansen (1:04.08)Emily Seebohm Ariarne Titmus DSQ

References