The women's 400 metre individual medley competition of the 2018 FINA World Swimming Championships (25 m) was held on 11 December 2018.

Records Prior to the competition, the existing world and championship records were as follows. Name Nation Time Location DateWorld recordMireia Belmonte 4:18.94Netanya12 August 2017Championship recordMireia Belmonte 4:19.86Doha3 December 2014

Results Heats The heats were started at 11:05.

Rank Heat Lane Name Nationality Time Notes 1 3 4 Katinka Hosszú 4:23.59 Q 2 2 3 Fantine Lesaffre 4:27.74 Q 3 2 6 Lara Grangeon 4:27.91 Q 4 2 5 Ilaria Cusinato 4:28.02 Q 5 3 1 Melanie Margalis 4:29.14 Q 6 2 4 Catalina Corro 4:31.02 Q 7 3 6 Sakiko Shimizu 4:31.12 Q 8 3 5 Miho Takahashi 4:31.13 Q 9 3 2 Abbey Harkin 4:33.23 10 2 2 Leah Smith 4:34.93 11 3 3 Zhou Min 4:35.34 12 1 3 Florencia Perotti 4:36.68 13 2 0 Nguyễn Thị Ánh Viên 4:37.28 14 3 7 Barbora Závadová 4:37.33 15 3 8 Jimena Pérez 4:37.42 16 2 7 Irina Krivonogova 4:37.54 17 2 1 Victoria Kaminskaya 4:38.49 18 3 0 Rebecca Meder 4:39.31 19 1 6 Claudia Hufnagl 4:39.76 20 2 9 Diana Durães 4:39.81 21 3 9 Katja Fain 4:40.00 22 1 5 Viktoriya Zeynep Güneş 4:40.67 23 2 8 Anastasiia Sorokina 4:41.43 24 1 2 Ruby Matthews 4:43.91 25 1 7 Lam Hoi Kiu 4:47.47 26 1 4 Tereza Horáková 4:48.83 27 1 8 Hamida Rania Nefsi 4:53.29 28 1 1 Wang Wan-chen 4:54.25 29 1 0 Sára Niepelová 4:54.87 30 1 9 Daniela Alfaro 5:01.36 NR

Final The final was held at 19:48.Final results

Rank Lane Name Nationality Time Notes 4 Katinka Hosszú 4:21.40 2 Melanie Margalis 4:25.84 5 Fantine Lesaffre 4:27.31 =NR 4 6 Ilaria Cusinato 4:27.88 5 3 Lara Grangeon 4:29.56 6 1 Sakiko Shimizu 4:31.07 7 7 Catalina Corro 4:31.63 8 8 Miho Takahashi 4:35.62

References