Yomif Kejelcha Breaks the Half-Marathon World Record He Used to Hold

Yomif Kejelcha ran 56:51 at the 21K de Buenos Aires on Sunday, taking back a half-marathon world record he lost in March to a run that has still not been ratified. World Athletics has carried Kiplimo’s 57:20 from Lisbon as the record since March, subject to a ratification that has not arrived. Its own profile page for Kejelcha, on Sunday morning, still marked his 57:30 from Valencia as the record.

Either mark leaves a wide margin. Kejelcha was 29 seconds faster than Kiplimo’s Lisbon time and 39 seconds faster than the 57:30 he ran in Valencia on Oct. 27, 2024. His net time in Buenos Aires was 56:50; world records are set on official time. The pace was 4:20 per mile.

One man has run faster over the distance. Kiplimo went 56:42 in Barcelona in February 2025, and World Athletics refused to count it.

The race left Avenida Figueroa Alcorta and Dorrego, in Palermo, at 8 a.m. in 43 F (6 C). Kejelcha broke clear at 7K and covered the last 14K alone, according to La Nación, which was first to report the result. Tadese Worku finished second in 59:20. Bereket Nega was third in 1:00:20 and Jonathan Kipkoech Kamosong fourth, one second back. Ignacio Erario was the first Argentine home in 1:00:59, short of the national record of 1:00:45, and Fotyen Tesfay won the women’s race in 1:03:57.

The rest of the field did not run unusually fast. Nega’s 1:00:20 was 37 seconds slower than the 59:43 he ran in March, and third place in this race a year ago was 23 seconds quicker than third place on Sunday. The layout is new: organizers cut the highway sections for 2026 and routed the race along Avenida 9 de Julio and Avenida Libertador. Kiplimo won here in 58:29 last August, itself a course record by 36 seconds. Kejelcha beat it by 1:38.

The Record He Did Not Break

Kiplimo’s 56:42 in Barcelona on Feb. 16, 2025 was the first half-marathon anyone had run under 57 minutes. World Athletics took almost a year to decide, and announced on Feb. 5, 2026 that there would be no record. Marathon Handbook reported then that the lead car had driven close enough to give him a slipstream, which the rules treat as assistance. World Athletics said later that the run “could not be ratified as a world record because the race conditions were not fully compliant with World Athletics rules.” Kejelcha’s 57:30 stayed on the books throughout.

Lisbon, and the Queue

Kiplimo returned to Lisbon on March 8 and won in 57:20, reclaiming the record with a time 38 seconds slower than the one that had been struck out. World Athletics footnoted its report “Subject to the usual ratification procedure.” On July 23 it ratified eight world records in one release, among them Sabastian Sawe’s marathon 1:59:30 and Tigst Assefa’s 2:15:41. The half-marathon was not among them.

Kejelcha has waited too. His 10K road record of 26:31 was run in Castellón on Feb. 16, 2025, the same afternoon Kiplimo ran 56:42 in Barcelona, and World Athletics ratified it on June 1 this year, more than 15 months later.

The Year He Is Having

Kejelcha turned 29 on Aug. 1 and had never raced a marathon before this spring. In London on April 26 he ran 1:59:41 and finished second, 11 seconds behind Sawe, in the first race in which two men broke two hours under World Athletics conditions. World Athletics called it the fastest marathon debut ever run and the second-fastest marathon of any kind. Kiplimo was third that day in 2:00:28.

He races next at the Valencia Marathon on Dec. 6, where Tesfay is also on the elite list. Valencia’s chief executive, Juan Manuel Botella, told Marathon Handbook in May that the race had not booked him to win in comfort. “He wouldn’t come to a marathon like Valencia to easily win in 2:03, nor would we hire him to run at 95%,” Botella said.

Before then, 56:51 has to clear the same process. The Buenos Aires layout is new this year, so the course Kejelcha ran on Sunday needs its own certification, and the two half-marathon world records before his produced one rejection and one wait that is now in its sixth month.