2025 World Championships
- July 27 – August 3, 2025 (pool swimming)
- Singapore, Singapore
- World Aquatics Championships Arena
- LCM (50m)
- Meet Central
- How To Watch
- SwimSwam Preview Index
- Entry Book
- Live Results
- Live Recaps
Hungary’s Hubert Kos did not swim the prelims of the 100 butterfly at the World Championships on Friday morning. Kos was the #6 seed in this event coming into the meet, entered with his lifetime best 50.55 that he set at the Hungarian Championship in April. It took a time of 51.58 to qualify for semifinals tonight.
Kos has already raced the 200 IM and the 100 back in Singapore, making it to the final and setting new best times in both events. He won bronze in the 200 IM with a 1:55.34 on Thursday night, and he took 4th in the 100 back with a 52.20.
At the Paris Olympics last summer, Kos finished 16th in the 100 fly in 52.22, which was about 1.5 off of his best time at that point. His performance in April of this year shaved .29 off of his previous lifetime best (50.84).
Kos was the Olympic champion in the 200 back last summer, bringing home the gold medal in a season-best 1:54.26.
The Hungarian record-holder in all three backstroke events, Kos competed in the semifinals of the 200 back on Thursday evening, advancing to the final in the #3 spot with a 1:54.64. He is also scheduled to race the 50 back on Saturday.
It is not known for sure why Kos did not race in the prelims of the 100 fly this morning, but he is set to take on the final of the men’s 200 back tonight in Singapore.

The 100 fly semi is like 20 minutes earlier than the 200 back final. He was always going to scratch.
“ It is not known for sure why Kos did not race in the prelims of the 100 fly this morning, but he is set to take on the final of the men’s 200 back tonight in Singapore.”
Real shot in the dark here but those two things might be related