16-Year-Old Yumeki Kojima Clocks 1:57.77 200 IM, Mizuki Hirai Hits 56.60 100 Fly

2025 AICHI PREFECTURAL SWIMMING CHAMPIONSHIPS

• Friday, July 4th & Saturday, July 5th
• Aichi Prefecture, Japan
• LCM (50m)
• Results

The 2025 Aichi Prefectural Swimming Championships took place over the weekend with several notable performances going down over the course of the two-day domestic competition.

Olympic finalist and University of Tennessee commit Mizuki Hirai was among the contenders with the 18-year-old logging wins in the women’s 50m and 100m fly events.

In the former, Hirai stopped the clock at a speedy mark of 25.78 to represent the sole swimmer of the field to delve under the 26-second barrier.

The outing checked in as a new season-best for the World Championships-bound athlete, overtaking the 25.94 notched at the Mare Nostrum Tour stop in Barcelona in May. The teen now bumped herself up the world rankings to take over slot #14 on the season.

As for the 100m fly, Hirai clocked two impressive performances, capturing the top seed out of the heats in 56.70 before dropping another .10 to ultimately take gold in 56.60.

Hirai opened in 26.41 and closed in 30.09 as the only competitor under the minute barrier in the race. This mark also represents a new season-best, eclipsing the 56.74 nabbed last month. She maintains her position as the 6th-swiftest female worldwide at the moment.

On the men’s side of the house, 25-year-old Shuya Matsumoto turned in a time of 21.97 to win the men’s 50m free while 16-year-old Yumeki Kojima earned the 200m IM victory in a super solid 1:57.77.

Matsumoto was also in that men’s 2IM race, snagging silver in 1:58.27 ahead of Kai Kawaguchi who bagged bronze well back in 2:02.25.

Kojima’s gold medal-worthy time of 1:57.77 hacked well over half a second off his former PB of 1:58.47. That previous career-quickest result was performed at the Japanese World Trials in March.

Kojima now becomes Japan’s 10th-best 200m IM performer in history and, at just 16 years of age, ranks 14th in the world this season.

For another point of reference, Kojima’s 1:57.77 would rank as a new U.S. National Age Group Record, erasing the boys’ 15-16 benchmark of 1:58.65 Maximus Williamson put on the books in 2023. The Japanese National High School Record remains intact for now, sitting at the 1:57.35 Olympic champion Kosuke Hagino produced at the 2012 Games.

Kojima’s swim here was a follow-up to the already-impressive result of the 4:11.67 400m IM stunner he established just last month, also in the Aichi Prefecture.

Top 10 Japanese Men’s LCM 200 IM Performers All-Time

1. Kosuke Hagino – 1:55.07, 2016
2. Daiya Seto -1:55.55, 2020
3. Tomoyuki Matshushita – 1:56.35, 2025
4. Kosuke Makino -1:56.80, 2025
5. So Ogata – 1:57.06, 2023
6. Hiromasa Fujimori – 1:57.21, 2016
7. Ken Takakuwa -1:57.24, 2009
8. Keita Sunama – 1:57.49, 2017
9. Takumi Mori – 1:57.71, 2024
10. Kojima Yumeki, 1:57.77, 2025

Finally, Yorihito Numata logged a time of 4:13.36 to take the men’s 400m IM event by over 10 seconds and inserts himself just inside the list of top 20 Japanese performers ever.