The women's 4 × 100 metre medley relay at the 2025 World Aquatics Championships was held on 3 August 2025 at the World Aquatics Championships Arena at the Singapore Sports Hub in Kallang, Singapore.

Background The United States will likely return their World Record and defending Olympic team. The team will likely be made up of Regan Smith, who holds the 100 metre backstroke world record; Gretchen Walsh, who holds the 100 metre butterfly world record; either Lilly King, or Kate Douglass on breaststroke; and Torri Huske. Projections suggest a time near 3:47.74, which would break their 3:49.63 record.

Australia, silver medallists at the 2024 Olympics, will likely feature Kaylee McKeown, Sienna Toohey, and Mollie O’Callaghan, while China, led by Tang Qianting and Zhang Yufei, will challenge them for silver. Canada, Japan, France, the Netherlands, Germany, and Great Britain are expected to target finals rather than medals.

Qualification Each National Federation could enter one team in the relay. The team had to be composed of swimmers who were also competing in the individual events, along with relay only swimmers who had to have met a specific qualifying time for the corresponding stroke and distance they would be swimming in the relay. Federations were only allowed to enter two relay-only swimmers for each relay they entered, though they could also enter relay-only swimmers from other relays which did not count toward this limitation.

Records Prior to the competition, the existing world and championship records were as follows.

The following new records were set during this competition. Date Event Nation Time Record 3 August Final 3:49.34

Heats Heats took place at 11:08.

Rank Heat Lane Nation Swimmers Time Notes 1 3 4 Katharine Berkoff (58.29)Lilly King (1:06.46)Claire Curzan (56.90)Simone Manuel (52.84) 3:54.49 Q 2 2 4 Kaylee McKeown (59.06)Sienna Toohey (1:06.95)Alexandria Perkins (56.73)Mollie O'Callaghan (53.06) 3:55.80 Q 3 3 2 Lise Seidel (1:00.98)Anna Elendt (1:05.34)Angelina Köhler (56.27)Nina Holt (53.85) 3:56.44 Q 4 3 5 Wan Letian (59.87)Yang Chang (1:06.49)Yu Yiting (57.18)Wu Qingfeng (53.16) 3:56.70 Q 5 3 3 Miki Takahashi (1:01.01)Satomi Suzuki (1:05.50)Mizuki Hirai (56.45)Nagisa Ikemoto (53.89) 3:56.85 Q 6 2 5 Kylie Masse (59.37)Sophie Angus (1:06.72)Ella Jansen (58.60)Mary-Sophie Harvey (53.63) 3:58.32 Q 7 2 2 Lauren Cox (1:00.08)Angharad Evans (1:06.03)Emily Richards (58.88)Freya Anderson (54.01) 3:59.00 Q 8 1 3    Neutral Athletes B Alina Gaifutdinova (1:00.12)Evgeniia Chikunova (1:06.71)Arina Surkova (57.81)Milana Stepanova (54.72) 3:59.36 Q 9 1 4 Olivia Nel (1:00.33 NR)Rebecca Meder (1:07.63)Erin Gallagher (57.31)Aimee Canny (54.20) 3:59.47 AF 10 3 8 Anita Gastaldi (1:00.95)Lisa Angiolini (1:07.45)Costanza Cocconcelli (57.60)Emma Virginia Menicucci (54.12) 4:00.12 11 3 6 Hanna Rosvall (1:01.79)Sophie Hansson (1:07.30)Louise Hansson (56.92)Sofia Åstedt (54.30) 4:00.31 12 2 7 Dóra Molnár (1:02.04)Henrietta Fangli (1:06.63)Panna Ugrai (58.21)Lilla Minna Ábrahám (54.34) 4:01.22 NR 13 3 1 Schastine Tabor (1:01.72)Clara Rybak-Andersen (1:07.24)Helena Rosendahl Bach (58.12)Julie Kepp Jensen (54.62) 4:01.70 14 3 9 Aviv Barzelay (1:02.10)Anastasia Gorbenko (1:06.49)Arielle Hayon (58.59)Lea Polonsky (55.25) 4:02.43 NR 15 1 5 Kim Seung-won (1:00.29)Ko Ha-ru (1:08.97)Kim Do-yeon (59.56)Hur Yeon-kyung (55.54) 4:04.36 16 3 7 Adela Piskorska (1:01.81)Barbara Mazurkiewicz (1:07.65)Zuzanna Famulok (1:00.02)Wiktoria Guść (55.92) 4:05.40 17 2 0 Carmen Weiler (1:00.69)Jimena Ruiz (1:10.12)Laura Cabanes (59.51)Maria Daza Garcia (55.17) 4:05.49 18 2 8 Theodora Drakou (1:01.46)Nikoletta Pavlopoulou (1:10.82)Georgia Damasioti (58.67)Anna Ntountounaki (55.25) 4:06.20 19 3 0 Levenia Sim (1:03.39)Letitia Sim (1:07.87)Quah Jing Wen (59.21)Quah Ting Wen (56.25) 4:06.72 20 2 1 Sum Yuet Cindy Cheung (1:02.93)Candice Gao (1:12.64)Hoi Ching Yeung (1:00.63)Li Sum Yiu (55.38) 4:11.58 2 6 Did not start

Final The final took place at 20:49.

Rank Lane Nation Swimmers Time Notes 4 Regan Smith (57.57)Kate Douglass (1:04.27)Gretchen Walsh (54.98)Torri Huske (52.52) 3:49.34 5 Kaylee McKeown (57.69)Ella Ramsay (1:06.49)Alexandria Perkins (56.26)Mollie O'Callaghan (52.23) 3:52.67 6 Peng Xuwei (59.94)Tang Qianting (1:05.48)Zhang Yufei (56.32)Cheng Yujie (53.03) 3:54.77 4 8    Neutral Athletes B Alina Gaifutdinova (59.87)Evgeniia Chikunova (1:06.19)Daria Klepikova (55.95)Daria Trofimova (53.16) 3:55.17 5 7 Kylie Masse (58.77)Sophie Angus (1:06.52)Summer McIntosh (57.35)Taylor Ruck (52.99) 3:55.63 6 3 Lise Seidel (1:01.02)Anna Elendt (1:04.90)Angelina Köhler (56.88)Nina Holt (53.22) 3:56.02 7 2 Miki Takahashi (1:01.78)Satomi Suzuki (1:05.57)Mizuki Hirai (56.46)Nagisa Ikemoto (53.82) 3:57.63 8 1 Lauren Cox (59.59)Angharad Evans (1:06.38)Emily Richards (58.12)Freya Anderson (53.86) 3:57.95

References