2025 JAPAN SWIM
The final day of action unfolded at the 2025 Japan Swim, the competition which represents the sole qualifying opportunity for the nation’s swimmers to add their names to the World Championships roster.
18-year-old Mio Narita saved her best performance for last, winning gold in the women’s 400m IM and setting a new Japanese National High School Record in the process.
After establishing herself as the top-seeded swimmer with a morning swim of 4:41.23 out of the heats, Olympic finalist Narita crushed a big-time result of 4:35.39 to ultimately take the gold.
Narita was one of two swimmers to get under the 4:40 barrier this evening, with Waka Kobori hitting 4:39.14 for the silver. Misuzu Nagoka, who turned 17 just days ago, rounded out the podium in 4:40.31.
As for Narita, her time this evening overtook her own previous Japanese National High School benchmark and lifetime best of 4:35.40 notched at last year’s Olympic Trials. Her slightly quicker performance keeps her ranked as Japan’s #3 performer of all time in this 4IM event.
Top 5 Japanese Women’s LCM 400 IM Performers All-Time
Yui Ohashi – 4:30.82, 2018
Sakiko Shimizu – 4:34.66, 2016
Mio Narita – 4:35.39, 2025
Miho Takahashi – 4:35.55, 2016
Ageha Tanigawa – 4:35.60, 2024
Both Narita and Kobori cleared the World Aquatics ‘A’ standard of 4:43.06 needed to qualify for Singapore and the pair ranks 4th and 5th, respectively, in the world this season.
2YuYitingCHN4:36.6303/203Abbie WoodGBR4:38.2402/154MioNARITAJPN4:38.7301/175WAKAKOBORI JPN4:39.7101/26View Top 26»