In the first major long course meet since last year’s Paris Olympics, many of the all-time swimming greats will be in attendance this week with the hopes of cementing their legacies. Many will be looking to make a major breakthrough as the march toward a new quad in Los Angeles 2028 begins.

Here are eight can’t miss races across the week-long program from the World Championships Arena.

Women’s 100m butterfly - July 28

The Players:

After nine world records in individual events at the World Short Course Championships last December, American Gretchen Walsh has become can’t miss television. Earlier this year, she became the first woman inside 55 seconds in the 100m butterfly, arguably her best event, as she will take aim at the world record once more. Her dominance thus far in 2025 has certainly been the stuff of legends, however she has yet to win an individual World or Olympic gold medal in long course, and this is easily her best chance.

Last year’s Olympic champion Torri Huske of the United States and last year’s World champion Angelina Koehler of Germany appear to be Walsh’s biggest adversaries in this event, but neither have swam inside 56 seconds this year. Walsh beat Huske head to head twice this year by almost two full seconds both times, but Huske has been known to show up when it matters so she can’t be counted out.

Australia’s Alexandria Perkins ranks third in the world this year at 56.42, as she will celebrate her 25th birthday during the heats of this event.

Men’s 50m butterfly - July 28

The Players:

After the 50m events were added to the Olympic line-up in three year’s time, many of the world’s best shifted their attention to the one-lap sprint, and this first one is completely wide open. Canada’s Ilya Kharun leads the world rankings at 22.68 after he won Olympic bronze in both the 50m and 100m.

France’s Maxime Grousset, who was the gold medal favorite in Paris last year in the 100m before fading to fifth, is ranked second at 22.70 ahead of Nyls Korstanje (22.72) of the Netherlands.

Switzerland’s Noe Ponti broke the world record in short course meters four times last year and was the World short course champion. The world record of 22.27 has been on the books for seven years and is certainly in danger of falling in 2025. Ponti is looking for a medal at these championships, something he has never achieved.

“That’s the only one I’m missing,” Ponti told World Aquatics earlier this year. “I have European - short course, long course, World Short Course, an Olympic medal but long course World Champs. (I’ve) never won a medal, only fourth. So I’d like to go home with a medal.”

This event could also be Singapore’s best chance for a medal on home soil with the likes of 27-year-old Tzen Wei Teong as he won silver in this event at the Commonwealth Games in 2022 and the Asian Games in 2023.

Women’s 100m backstroke - July 29

The Players:

The four fastest swimmers all-time will square off once again with world record holder Regan Smith of the United States looking for her first head to head win over two-time reigning Olympic champion Kaylee McKeown of Australia.

Smith leads the world rankings at 57.46 over McKeown’s 57.65, with the Australian winning the last two Olympic golds in the event along with the 2023 World title. Smith’s 2022 World title came without McKeown in the field as these two have transformed the backstroke field globally since they each made their debuts in 2017.

If anyone can take these two down, American Katharine Berkoff was leading the Olympic final for 65 meters before she wound up with the bronze. She has more speed than anybody in the world and will just need the closing speed to take down the two fastest ever.

Canada’s Kylie Masse sits fourth in the world rankings and has swum in every major 100m backstroke final since Rio 2016. Before McKeown and Smith traded the world record and world title, Masse won two World titles in 2017 and 2019, and is still in the thick of it at age 29 in 2025.

Men’s 100m backstroke - July 29

The Players:

It’s a race that has no clear favorite. South Africa’s Pieter Coetze ripped a 51.99 in Germany a few days ago at the World University Games, while Kliment Kolesnikov led the world rankings until then at 52.04. Coetze became the eighth in history to swim inside 52 seconds as the world record of 51.60 looks to be in serious danger come July 29.

Oliver Morgan of Great Britain swam 52.12 in April while 18-year-old Miron Lifintsev looks dangerous as well with his career best sitting at 52.08 from last year. Lifintsev was the World Short Course champion last year where he took the world junior record down with him.

Last year’s Olympic champion and the world record holder Thomas Ceccon of Italy has only been as fast as 53.31 this year, but is always flying under the radar. However he will need a heroic swim to win the gold medal this year as the field is faster than it has ever been. Last year was the first time at a major meet it took under 53 seconds to make the final, while eighth place in the year currently is 52.55.

Add in 200m Olympic champion Hubert Kos, European champion Apostolos Christou and the 2017 and 2019 World champ Xu Jiayu, It could take a 51 to just get on the podium in what will be a can’t miss race

Men’s 100m freestyle - July 31

The Players:

This event will feature the entire podium from the Paris Olympics, as they each have won the World title the last three years. Pan Zhanle won the Olympic gold last year and broke the world record at both the World Championships and Olympics, will face tough opposition in 2023 World champ Kyle Chalmers and 2022 World champ David Popovici.

The Romanian Popovici appears to be in top form this year, swimming 46.71 to lead the world rankings, which was faster than his 46.86 world record he set in 2022 which was beaten by Pan twice in 2024. Pan has only been as fast as 47.77 this year but will not be counted out this year, even if he is ranked ninth in the world amongst those qualified for the championships.

Two upstarts, Jack Alexy of the United States and Gui Caribe of Brazil, are having career years. Alexy, the silver medalist from the Worlds in 2023, became the sixth swimmer inside 47 seconds in June, while Caribe swam 47.10 in May to enter the top ten all-time.

Like the aforementioned 100m backstroke, it could be the fastest field ever assembled come July 31 - the fastest it took to get into a major final was 47.82 back in Tokyo 2020. This year, nine men have been faster than that in the world rankings as some big names could end up missing the grand final.

Women’s 200m breaststroke - August 1

The Players:

Last year’s Olympic champion Kate Douglass will face off with world record holder Evgeniia Chikunova for the first time in long course meters. Douglass took the first matchup at the World Short Course Championships in December, but Chikunova swam 2:20.36 this year while Douglass was 2:20.78.

Chikunova, age 20, swam 2:17 two years ago to set the global mark while Douglass has only been as fast as 2:19. Both of them have an incredible distance per stroke and it will be a beautiful display of breaststroke. If either of them falter, look for the 100m world leader of Angharad Evans or the World Short Course bronze medalist Alex Walsh to make a move.

Men’s 4x200m freestyle - August 1

The Players:

  • Great Britain
  • United States
  • Australia
  • Republic of Korea

Great Britain has won the last two Olympic gold medals and the 2023 World title, all with the same four swimmers. Those same four, Matthew Richards, James Guy, Duncan Scott and Tom Dean return once more in 2025 and have no intentions of slowing down leading into Los Angeles 2028.

However, the United States team threw down some quick times at their World Trials in June, led by short course meters world record holder Luke Hobson at 1:43.73, who is having a career year. Rookies Gabriel Jett (1:44.70) and Rex Maurer (1:45.13) followed, with 19-year-old Henry McFadden (1:45.22) in fourth. The team is relatively inexperienced after Hobson, but the aggregate time is faster than that of the British team from its trials in April.

“The US have got some real firepower this year, we will try and meet fire with fire,” Matthew Richards said at a British Swimming press conference. “We will be getting in there to have a good scrap and obviously going after the win but I am expecting us to have a real head to head in that race and it should be a good one to watch.”

Great Britain and the United States are expected to challenge for the gold, with Australia and Korea likely to contend for a medal.

Women’s 800m freestyle - August 2

The Players:

Perhaps the race of the entire championships, the two best swimmers in the entire world will square off in the 800m freestyle for the very first time on the world stage. Katie Ledecky has been unbeatable at the World Championships and Olympics for 13 years, with her only loss coming at a small domestic meet in February 2024 to the likes of Summer McIntosh.

Ledecky broke her own world record in a memorable swim in May of this year, her first best time in the event since August 2016. In June, McIntosh got closer to Ledecky’s than anyone had ever been before, setting up a huge matchup for the penultimate night of the swimming programme.

“I think there’s many reasons why I picked the 800m,” McIntosh said at a Zoom press conference before her training camp in Japan earlier this month. “I think it’s, in my opinion, the biggest challenge with of course Katie being so strong and in her top form right now this season. That matchup will be awesome.”

Will it take a world record to win? Will Ledecky extend her winning streak and win her seventh World title in the event? If McIntosh wins, it would add to her already growing legacy as one of the greatest of all-time. If Ledecky wins, it would perhaps be the biggest challenge of her already illustrious career.

The swimming community will be watching with bated breath during the eight minute race on August 2, and it could certainly live up to the billing.