2025 World Championship Previews: Walsh Alone On The Mountaintop In Women’s 100 Fly

2025 World Championships

• July 27 – August 3, 2025 (pool swimming)
• Singapore, Singapore
• World Aquatics Championships Arena
• LCM (50m)
• Meet Central
• Live Results
• SwimSwam Preview Index

BY THE NUMBERS – WOMEN’S 100 BUTTERFLY

• World Record: 54.60– Gretchen Walsh, USA (2025)
• World Junior Record: 56.33– Mizuki Hirai, JPN (2024)
• Championship Record: 55.53 – Sarah Sjostroem, SWE (2017)
• 2023 World Champion – Zhang Yufei (CHN), 56.12
• 2024 Olympic Champion – Torri Huske (USA), 55.59

This event looks like one of the clearest with regards to the gold medal. Gretchen Walsh holds an absolutely huge lead in the season rankings, and will be gunning for her first individual long course world title.

Behind her will be a fierce battle for bronze between two stalwarts of the last four years and two up-and-coming sprinters. There should then be another group battling for the final few spots in the top-eight, with several swimmers aiming to go one better than they managed in Paris.

Time To Grasp The Opportunity For Walsh

Gretchen Walsh set the world record once again this season, becoming the first woman to break 55 seconds en route to setting the new standard of 54.60. She was sub-55 again at U.S. Nationals to go 54.76, and holds a 1.82 second lead in the season rankings. She owns the seven fastest swims in history in the event now, and has swum faster than the winning time in Paris on four occasions already this year.

This is Walsh’s best event, and she has truly made it her own this season. All she needs now is a world title, and as this will be Walsh’s first individual final of the championships it is a prime opportunity for her to claim her first major individual long course title.

She made a habit last year of swimming her best in the semi-finals, doing so at both U.S. Trials and the Olympics. That saw her finish 2nd in Paris in an event where she was the hot favorite, and she will be eager to avoid a repeat this year. However, with Huske not looking quite in the same form as last season and Walsh’s buffer even larger than this time last year, it is almost impossible to see the gold coming from anywhere else.

Four Into Two Doesn’t Go

Behind Walsh are four swimmers separated by just 0.17 seconds, all of whom will be intending to stand on the Podium at the end of Day 2. The one who may have the slight edge is Olympic Champion Torri Huske, who is the third-fastest swimmer in history with her 55.52 from Olympic Trials last year. She went on to win gold in Paris in 55.59, running down Walsh in the final meters, but has only been 56.59 so far this season.

After a strong NCAA season and looking in great form in freestyle, we can expect Huske to be back under 56 seconds in Singapore. She has been on the podium in each of the last three years, winning two golds and a bronze, and has the highest ceiling right now of this group. Another American 1-2 is likely.

Torri Huske (photo: Jack Spitser)

Angelina Kohler may fancy herself the strongest contender to the American’s, with the 2024 World Champion holding a lifetime best of 56.11 from Doha last year. She has been 56.42 this season, ranking joint-2nd, and set a new German Record in the 50 fly earlier this year. She was 4th in Paris last year in 56.42, 0.21 seconds off bronze. Getting back down to the 56-lows she swam in semis and the final in Doha could be the key to the podium for her.

Alexandria Perkins has seen immense growth this year, dropping from 57.10 to 56.42 already. That ranks her joint-2nd in the world for the season, tied with Kohler, and should be the foundation for her to make her first major long course final. She took bronze at short course worlds in an Oceanian Record of 55.10, and was 3rd at Australian Trials in the 100 freestyle with a swim of 53.53, and after bowing out in the semi-finals in Paris after adding time from Trials should have the buffer to be in the top eight even if she is not at her best.

With the retirement of Emma McKeon, Perkins has stepped into the gap to become the main fly swimmer for Australia. She may not quite keep the same rate of progression to Singapore, but count her out at your peril.

Zhang Yufei was the 2023 world champion, beating out Torri Huske and Maggie MacNeil to take the gold, and won bronze in Paris last summer. She holds a best of 55.62 from 2020 and was 55.86 at the Asian Games at the start of last season, but hasn’t been able to hit those highs so far this year.

She was also a second slower at Chinese Nationals this year than in 2024, taking second in 57.39. She has the ceiling to medal in this race, but doesn’t quite look to have the same sharpness we’ve seen in recent years.

A Strong Local Contingent

The swimmer who took the win in Beijing in April ahead of Zhang was Yu Yiting, generally better known for her IM. She was 57.30 there, half a second slower than her best of 56.82 from last year, but this will be her first time swimming the event internationally.

She has only broken 57 seconds once though, and this event comes on the same day as her primary event, the 200 IM. She was fourth in that in Paris, and with no Kate Douglass will fancy her chances to make the podium, making it unlikely we see her here.

Mizuki HIRAI (JPN)
credit Roldy Cueto

Mizuki Hirai owns the World Junior Record in this event, with that mark of 56.33 from last April standing as her best time. She has been 56.60 already this season to rank 6th in the season rankings and 5th out of those who will be in the event at Worlds.

After making the final in Paris last summer, where she finished 7th, she will be eyeing a return trip closer to home. She did add time through the three rounds last summer however, going 56.71/56.80/57.19, and will need to make sure she’s under the 57-second mark in the semi-finals to ensure she makes the final.

The other Japanese entrant is a familiar face in Romano Ikee, whose best of 56.08 ranks her 10th all-time. That did come back in 2018 before she was diagnosed with, and then recovered from, leukaemia. Her best since her recovery is the 57.03 she is entered on, and she has been 57.53 so far this season. She may need to be right on her recent best to make the top eight, but should earn the right to compete in the semi-finals.

The Final Is The Aim For The Europeans

Louise Hansson is the second fastest European entrant in 56.93, the time she went in the semi-finals in Paris last year. She ended up finishing 8th in the final in 57.34, but that semi-final swim was her fastest since the world final in 2022 where she was 56.48.

She took bronze at the Doha world championships in 56.94, and has been 57.35 so far this season. Having made every major final in the last four years other than in 2023 where she was 9th, seeing her sneak into the final would not be surprising.

While Hansson has the faster entry time, Roos Vanotterdijk and Tessa Giele have both been faster so far this year. Vanotterdijk set the Belgian record in April this year, one of six that she has set already this calendar year, and won gold at the European U23 Championships by nearly a second.

She does have a very busy schedule of seven individual events, including the 200 IM on the same day as the 100 fly, but this will likely be the one she goes with and its timing in Day 1 will ensure that she is fresh.

courtesy of Fabio Cetti

Tessa Giele has dropped two-tenths of a second from her 100 fly time so far this season, and had a stellar short course season in the event which culminated in her taking silver at worlds in the seventh-fastest swim all time.

She is entered on the 57.17 she swam at the Bergen Swim Open in April, and neared that mark again in June at the Dutch Championships with a 57.35. She may need to drop some time to final, and added three-tenths last year in Paris, but with her form this year could be a wildcard.

The Greek pair of Anna Ntountounaki and Georgia Damasioti come in with times in the 57-mid range, and will likely top out as semi-finalists. Damasioti finished second at the recent European U23 Championships in 58.06, where she also won the 200 fly, while Ntountounaki placed 5th at the 2024 World Championships, although did then miss the semi-finals in Paris. She does however rank 8th this season out of swimmers entered in the event, so if she can be near her Greek Record will be fighting for the top-eight.

The Verdict

Walsh is the clear-cut favorite for gold in this race, but the podium behind her is a little murkier. Torri Huske should be one of the two other swimmers in the medals, and we’ve picked Angelina Kohler to round off a strong 18 months with bronze.

Zhang Yufei has the pedigree but has not looked quite at the top of her game this year, and Alexandria Perkins has only broken 57 seconds twice, both on the same day, and predicting her to continue down to the 56-lows this summer may be premature.

SwimSwam’s Picks

Dark horse: Erin Gallagher (South Africa) – Gallagher had some big swims in the 100 fly last year, dropping the African record down to 57.59 in Doha before lowering it again at April’s South African Championships to 57.32. She was 57.90 to finish 14th in Paris, but if she can get back to 57-low range and drop even more time she can be in the conversation to final. She holds a season best of 58.51 but expect her to be quicker than that in Singapore.