John Korir Aims to Break Kelvin Kiptum’s World Record at the 2025 Chicago Marathon

Reigning Boston Marathon champion John Korir is preparing for the race of his life — an attempt to break the late Kelvin Kiptum’s marathon world record of 2:00:35, set on the streets of Chicago in 2023.

Korir, 28, will return to defend his title at the Chicago Marathon on October 12, but this time with a bold target in mind: a new personal best of 2:00:30. Achieving it would not only secure back-to-back victories in Chicago but also eclipse Kiptum’s mark by five seconds.

“The target my coach and I have set for ourselves in Chicago is to lower my personal best and clock 2:00:30,” Korir told The Star. “My body is in good shape, I am injury-free, and I feel great.”

Chicago’s course is renowned for producing fast times — flat, competitive, and recognized by the International Olympic Committee as a “historical world record course.” Korir believes its layout, combined with his current form, offers the perfect stage for a record-breaking run.

His 2025 season has already been outstanding. In April, Korir won the Boston Marathon in 2:04:45, becoming, alongside his brother Wesley Korir (the 2012 Boston champion), the first siblings ever to claim Boston titles. In July, he added another victory at the Boilermaker 15K, clocking 42:44 ahead of a strong field that included Hillary Kipkoech and Abbabiya Simbassa.

In last year’s Chicago Marathon, Korir set his current personal best of 2:02:44, leading Ethiopia’s Mohamed Esa (2:04:39) and Kenya’s Amos Kipruto (2:04:50) to the podium. This year, he expects even fiercer competition but remains focused on the ultimate goal.

“All eyes will be on me because I am the defending champion,” Korir said. “My coach and my brother keep telling me I can do it, and I believe I can.”

If Korir succeeds, he will not only defend his Chicago crown but also become the first man in history to run under 2:00:30 in a record-eligible marathon.

posted Monday August 11th
by Boris Baron