2025 World Junior Swimming Championships
- August 19-24, 2025
- Otopeni, Romania
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GIRLS 100 BUTTERFLY – Finals
- World Record: 54.60 – Gretchen Walsh, United States (2025)
- World Junior Record: 56.33 – Mizuki Hirai, Japan (2024)
Championship Record: 57.02 – Mizuki Hirai, Japan (2025)
TOP 8:
- Mizuki Hirai (JPN) – 56.87 (Championship Record)
- Audrey Derivaux (USA) – 57.74
- Gong Zhenqi (CHN) – 58.10
- Charlotte Crush (USA) – 58.26
- Clare Watson (CAN) – 58.69
- Caterina Santambrogio (ITA) – 58.78
- Serafima Fokina (NAB) – 59.04
- Aliisa Soini (FIN) – 59.13
Mizuki Hirai was simply dominant in tonight’s 100 fly final, lowering her own championship record of 57.02—set just last night—to secure the World Junior Championship title by nearly a full second. Hirai, who won the 100 fly at the 2022 World Junior Championships as well, has now claimed her 2nd World Junior title and 3rd medal in this event, as she took bronze in 2023.
Hirai holds the World Junior Record in the girls’ 100 fly at 56.33, set back in June of 2024 at a high school meet in Japan. Despite not hitting a personal best, Hirai’s swim tonight showed remarkable consistency, as it is her 7th time under the 57-barrier.
Splits Comparison:
| Hirai – Finals | Hirai – Semifinals | Ikee – Old CR | Hirai – WJR | |
| 50 | 26.55 | 26.65 | 27.14 | 26.26 |
| 100 | 56.87 (30.32) | 57.02 (30.37) | 57.25 (30.11) | 56.33 (30.07) |
Compared to last night, Hirai was marginally faster on both 50s. However, akin to her semi-finals swim, she was out the fastest of the field, gaining an early lead and never relinquishing it. After opening in 26.55, she came home in 30.32, which was also the quickest closing split, to touch ahead of of American Audrey Derivaux‘s 57.74.
Hirai, an Olympic finalist, has already posted a series of top performances at the World Junior Championships this week, though this marks her first individual win of the meet. She picked up a gold medal as part of Japan’s winning mixed 4×100 medley relay (3:45.57), won silver in the 50 fly (25.66) and placed 7th in the 100 free (55.01). The only event remaining on her schedule is the girls’ 4×100 medley relay at the end of tonight’s session, where Japan is seeded 5th.
