Ako Koseki

JapanJapanActive
Born
Sep 10, 2008 (18 years old)
Events
400 m

Ako Koseki is a Japan sprinter, born on September 10, 2008. She competes primarily in the 100m, 200m and 400m.

Her personal bests include 12.84 in the 100m, 25.73 in the 200m, 57.73 in the 400m and 41.36 in the 300m. She is currently active on the international athletics circuit, representing Japan.

Personal best · 400 m57.73
2026 season best26.18Jul 18, 2026
2026 season best
Last competition99th Hokkaido Athletics ChampionshipsJul 18, 2026 · 26.18
99th Hokkaido Athletics Championships

As of Nov 14, 2026: 400 m 57.73, 2026 season best 26.18 (Jul 18, 2026) · Last competition: 99th Hokkaido Athletics Championships, Jul 18, 2026, 26.18 · 18 years old

Personal bests

WA points calculator →
DisciplineResultAll-time
100mHakodate 2025Japan 100 m all-time list12.84832 pts–
200mObihiro 2025Japan 200 m all-time list25.73876 pts–
400mAsahikawa 2025Japan 400 m all-time list57.73915 pts–
300mHakodate 202541.36889 pts–

Progression

SeasonDisciplineResultWindDateCompetitions
2026200m 26.18+0.8Jul 18, 202699th Hokkaido Athletics Championships
2025100m 12.84+0.9Aug 9, 20252025 National Athletic Meet Hokkaido representative selection meeting
2025200m 25.73-0.8Sep 26, 202541st Hokkaido High School Rookies’ Meeting
2025300m 41.36–Aug 10, 20252025 National Athletic Meet Hokkaido representative selection meeting
2025400m 57.73–Jun 17, 202578th Hokkaido High School Championships
2024200m 26.02+1.6Jul 13, 202497th Hokkaido Athletics Championships, Athletic Track, Abashiri
2024400m 57.94–Sep 18, 202440th Hokkaido High School Rookies’ Meeting, Irie Stadium, Muroran
FAQ

Frequently asked questions

Ako Koseki's 400 m personal best is 57.73, set on Jun 17, 2025 in Hanasaki Athletic Field, Asahikawa (JPN).

Ako Koseki competes in the 400 m.

2026 season best: 26.18, set on Jul 18, 2026. Last competition: 99th Hokkaido Athletics Championships on Jul 18, 2026, 26.18.