2025 World Championship Previews: Threats Throughout The Field In Men’s 100 Fly

2025 World Championships

• July 27 – August 3, 2025 (pool swimming)
• Singapore, Singapore
• World Aquatics Championships Arena
• LCM (50m)
• Meet Central
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BY THE NUMBERS – MEN’S 100 BUTTERFLY

• World Record: 49.45  – Caeleb Dressel, USA (2021)
• World Junior Record: 50.62– Kristof Milak, Hungary (2017)
• Championship Record: 49.50 – Caeleb Dressel, USA (2019)
• 2023 World Champion – Maxime Grousset (FRA), 50.16
• 2024 Olympic Champion – Kristof Milak (HUN), 49.90

Returning Olympic Finalists

• Silver- Josh Liendo (CAN), Bronze- Ilya Kharun (CAN), 4th – Noe Ponti (SUI), 5th- Maxime Grousset (FRA), 6th- Nyls Korstanje (NED), 7th- Matt Temple (AUS), 8th- Naoki Mizunuma (JPN)

We will be missing two of the five men to have broken 50 seconds in the event in Singapore, with World Record holder Caeleb Dressel and European Record holder Kristof Milak sitting the summer out. Those are the #1 and #2 swimmers in history, but even without them this event is staggeringly quick

There are 14 men entered who have a best time under 51 seconds, and another three who have been 51.0. It’s inevitable that something will have to give, and that could result in a semi-finals for the ages. At the front though there are four men ahead of the field who each have designs on taking home the title, led in the 2024-25 season rankings by none other than the 2023 World Champion.

Gunning For Gold

Maxime Grousset won gold at the 2023 World Championships in Fukuoka in a time of 50.14, a huge new French record and best time. He couldn’t quite match that in Paris as he fell to 5th in the final, posting a 50.75 that was his slowest time of the three rounds – his time of 50.41 from the semi-finals would have been enough for bronze.

He’s back on top of the world now, at least in the 2024-25 season rankings. He clipped three-hundredths of a second from his lifetime best at the French Elite Championships at the start of June to vault up to the #1 spot and cement his claim for the gold this summer. He has two flying splits under 50 seconds as well, demonstrating his ceiling, and is someone who will be doing the buffeting rather than being buffeted if the race is tight. The only man here to have stood on top of the podium at a major summer meet, it would not be a surprise to see him do so again.

Ilya Kharun (photo: Jack Spitser)

Eager to return to the podium after finishing 2-3 last year will be the Canadian pair of Ilya Kharun and Josh Liendo. They sit 3rd and 4th in the world rankings this season with times of 50.37 and 50.46, with Kharun’s marking a new best time. They both swim in the NCAA, Liendo at Florida and Kharun at Arizona State, and are both coming off excellent seasons in yards which saw them win a combined three national titles.

Kharun also had a stunning short course meters season that saw him flash some serious speed in the 50 fly – a shift toward speed from previous seasons while training under sprint-focused coach Herbie Behm. That has translated to long course already as he has slashed more than half a second from the Canadian record in the event, and is probably now the best three-distance fly swimmer in the world – 22.68 in the 50, 50.37 in the 100 and 1:52.80 in the 200.

Having that ability in both the 50 and the 200, this event could be Kharun’s sweet spot. However, it is his Canadian teammate who has had the most success recently and owns the National record of 49.99 from Paris, which ranks him 5th all-time. He won bronze in 2022 and silver in both 2023 and 2024, showcasing the greatest consistency of anyone in this field.

However, Liendo has barely dropped from Trials in the last two years, only 0.02 seconds in 2023 and 0.07 seconds in 2024. Add in that he was 0.09 seconds slower at worlds than Trials in 2022, and history indicates that we may see ‘only’ a 50-mid from him in Singapore. He was slower in all his events this year than the previous two though so this could be due to a different approach to his taper, but it is something to keep an eye on.

Noe Ponti is the fourth member of this group, and came into Paris last summer in red hot form having posted a new Swiss record of 50.16 earlier in the year. However, the bronze medalist from Tokyo failed to make it back to the podium in Paris as he finished 4th in 50.55, a tenth back from Kharun.

Onto this season he nearly matched his personal best of 50.16 back in April with a swim of 50.27, and is coming off a stunning short course season where he rewrote the record books in both the 50 and 100 fly, setting a time of 47.71 in the latter. He’s held his form into the summer well so far, going 50.4 at the Sette Colli at the end of June, but he has struggled to perform at his best at a major summer meet since Tokyo. If he can swim a personal best in the summer for the first time since 2021 he’ll be a strong contender in the title fight.

A Strong European Contingent

Hubert Kos beat Kristof Milak at Hungarian nationals earlier this year, and his time of 50.55 ranks him 6th globally this year. However, he has a busy schedule of five individual entries and struggled in this event in Paris, where he placed 16th in the semi finals, adding over a second to his entry time. This is probably the most likely event for him to drop as well, with it clashing with the 200 IM where he could have a big drop in store after another year under Bob Bowman.

World Aquatics Championships – Doha 2024
02 – 18 Feb 2024
credit Fabio Cetti

Nyls Korstanje has had incremental improvements over the last few seasons that have made him first a finalist and now an outside medal contender. He has a lot of early speed and tends to use it – he was out 23.23 in Paris, fastest of all the finalists – but has swum his best in the early rounds in the last couple of years. With a lifetime best of 50.59 he will dare the four favourites to run him down.

Andrei Minakov won silver in what was until recently a Russian record of 50.83 back at the 2019 World Championships. He took the win at this year’s Russian Nationals in a new best of 50.82, and looks back in top form after returning to the sub-51 club and a fantastic NCAA season.

There are a few other men coming in with entry times right on what it took to make the final last summer. Included amongst those are previous finalists Jakob Majerski (POL), Diogo Ribeiro (POR), Simon Bucher (AUT) and Gal Cohen Groumi (ISR), all of whom hold their respective national records. Majerski owns the fastest time of the quartet in 50.92 but it was Ribeiro who was on the top step of the podium at the 2024 World Championships, ahead of Majerski and Bucher. Chen Juner joins that group of contenders after a 51.03 swim from Chinese nationals, but has generally performed better at National than International level.

Dynamic Duos

USA – Shaine Casas and Thomas Heilman

Casas set his 2nd-fastest time ever to win U.S. Nationals in 50.51, a time that ranks him 5th in the world this year. He has a best of 50.40, which is certainly enough to be in the medal conversation, but has made a habit of not performing his best in major finals. He added in the 200 IM last year to miss the final, and added pretty significantly in this event at the 2024 World championships in Doha where he did not break 52 seconds.

However, he had a good short course season and has set multiple best times in long course as well this season. Casas could be a solid pick to be near or at his best and final here.

The swimmer he beat out in Indianapolis, Thomas Heilman, also has something to prove in this event. He missed the semi-finals in Paris last summer, but set a new best of 50.70 at U.S. Nationals. He’s been stronger internationally in the 200, but he has enough speed to be a threat in this event as well. After not making the team in the 200 fly this year, he can focus on the 100 which may be all he needs to make the latter rounds.

Japan – Katsuhiro Matsumoto and Naomi Mizunuma

Matsumoto won Japanese trials this year, but Mizunuma has had the most success on the international stage. He took silver in 2022 behind Kristof Milak, but hasn’t been able to follow that up as he missed the final in 2023 and 2024. He does however hold the Japanese record with the 50.81 that he swam in the semi-finals in 2022, and was 51.08 in Paris last year before placing 8th in the final.

Matsumoto’s best is not far behind his compatriot, holding a best of 50.96 and has been 51.10 this season to Mizunuma’s 51.47. He was only 15th in Paris, but if he’s near his best will be a challenger for the top eight.

Italy – Thomas Ceccon and Federico Burdisso

Ceccon is entered in this event for the first time at Worlds, but is the fastest Italian so far this year after dropping a personal best time of 51.26 at Australian Nationals. He was only 48.41 in the 100 free there, seven-tenths from his best, so breaking 51 seconds in the 100 fly is not out of the question. As the 50 fly world champion from 2023 in a time of 22.68, he has plenty of speed to lean on for this event.

Burdisso has not been able to consistently replicate the form that saw him win bronze at the Tokyo Olympics in the 200 fly, but holds a best of 51.39 in the 100 and split 50.63 as Italy upset the U.S. in the medley relay in 2022. He was just 51.83 at Italian Trials so will need to drop a fair chunk of time both from his season best and personal best to be in the hunt.

Australia – Matt Temple and Jesse Coleman

Temple is the 8th-fastest swimmer of all time thanks to his 50.25 from the Japan open back in December 2023, but added significantly in Paris to finish seventh in 51.10. He’s yet to win a long course world or Olympic medal in this event and has tended to add time from Australian Trials in his major summer meet. Having only been 51.00 this year, that could spell trouble unless he can reverse the trend.

Matthew Temple courtesy of Fabio Cetti

Coleman set a big lifetime best to take second behind Temple in Adelaide and qualify for his first senior world championship team after finishing 4th at last year’s trials. He ranks as the 4th fastest Australian ever in the event after dropping more than four-tenths of a second this year, and his best of 51.09 is 0.01 away from what it took to make the final last summer.

The Verdict

Grousset owns the world lead this season and looked in fantastic shape at French Trials. He’s tended to drop time in the summer, especially in butterfly, and has been a major medal threat in the 100 fly ever since 2023. Having posted his fastest in-season time by a distance and with Milak and Dressel out, he could be the next man under 50 seconds in Singapore to take top spot.

Kharun has looked phenomenal in long course so far this year, and we’re tipping him to come through to take silver. Herbie Behm’s sprint revolution at Arizona State has been an absolute boon for the Canadian, and that new early speed combined with his trademark back end could be incredibly dangerous. His teammate Liendo may not quite hit the heights of last year but should have enough to make the podium

Ponti has been in great form so far this year, but it’s getting on for four years since he was last at his best in a major long course final. He’s done a lot of racing already this season and could miss the podium here. It’s easy to forget that he had a pretty phenomenal short course season in fly last year as well and ended up fourth in Paris – a long season could catch up with him again.

Behind these four there is a distinctly European flavor to the field, and we think to the final too.

SwimSwam’s Picks

Dark horse – Clement Secchi (France) – Grousset’s teammate will make his second senior international appearance in Singapore, after taking silver at the French Elite championships in a lifetime best of 51.06. That may only be a tenth quicker than he was at this point last year, but he had dropped 1.4 seconds to get to that point in the 2023-24 season. He added four tenths to bow out in the semis in Paris, but if he’s saved his speed for the summer this time could go one better in Singapore.