Each time 18-year-old Summer McIntosh walked the deck at the Canadian Swimming Trials in Victoria, the swimming world stopped and watched. After three gold medals and a silver at the Paris Olympics in 2024, she showed no signs of any post-Olympic funk in her domestic trial run for a five-event program for the World Aquatics Championships in Singapore.
Relocating from Sarasota in the United States and coach Brent Arckey, to the south of France in Antibes with coach Fred Vergnoux, her swimming went up another level in 2025. In Victoria at the Canadian Trials, she broke three world records – taking back the 400m freestyle to her name at 3:54.18, as well as lowering her own mark in the 400m IM to 4:23.65, nearly three seconds ahead of the next fastest all-time. The 200m IM was a new addition as she wiped Katinka Hosszu’s ten-year-old world mark from 2015 off the books, swimming 2:05.70.
Image Source: Quinn Rooney/Getty Images
McIntosh became the first swimmer since Michael Phelps in Beijing 2008 to set three individual world records in the same meet, and the first woman to do so since Inge de Bruijn in Sydney 2000.
Arguably though, her two most impressive swims came in the two where she didn’t break the world record.
If one would poll 100 anonymous people on the deck at the World Aquatics Championships this week about which two women’s world records are the hardest to break, the 200m butterfly and 800m freestyle would be high on that list.
Since initially breaking the 800m mark in 2013, Katie Ledecky has dominated the 16-lap event, bringing the record down to 8:04.12 this year. At that point in May 2025, the second fastest swimmer of all-time? Summer’s 8:11 from February 2024.
On the second night of the Canadian Trials, McIntosh, fresh off the 3:54 in the 400m, gave the 800m world record a scare, something no one besides Ledecky had done in years, swimming 8:05.07. For 800 meters, the swimming world followed with bated breath as she was toe to toe with the greatest female swimmer of all-time’s greatest swim.
No one had been able to touch Ledecky’s 8:04 for nine years, so when McIntosh got within a second of it, the swimming community could not believe what they were seeing.
Similarly, in the 200m butterfly, Liu Zige’s 2:01.81 has stood as the standard since 2009. The closest anyone had been since? Summer’s 2:03.03 en route to winning the Olympics last year. The 2:01 has been so out of reach that hardly anyone has given the record any thought of being broken in 16 years. Was that the peak of human performance? Will we ever get faster?
In the last ten years, only three women have been inside 2:04, hardly a sniff away from that 2:01. On the fourth night of Canadian Trials, McIntosh swam 2:02.26, sitting under the record pace for 150 meters. What was once thought to be an unbreakable record suddenly seemed mortal.
“I think people tend to focus on the three world records but those other two races at Trials were honestly two of my favorites,” McIntosh told reporters at a virtual press conference before the championships. “I would say the 200m fly was honestly my second favorite race that I did there other than the 400m freestyle, just timewise and how I split it.
“I’m really pumped to get another run at it in Singapore and see how things work out. My main goal in Singapore is to get my hand on the wall first as many times as I can rather than the time but in doing so it can also come with a couple world records, hopefully, so we will have to see.”
Image Source: Katie Ledecky v. Summer Mcintosh in the Women’s 400m Freestyle Heats at the 2023 World Aquatics Championships in Fukuoka, Japan. (Clive Rose/Getty Images)
McIntosh’s success in the 800m freestyle sets up an intriguing duel between herself and Katie Ledecky on the penultimate night of competition at the World Aquatics Championships. After winning four individual medals in Paris last year, McIntosh has expressed interest in taking on a fifth event for Los Angeles 2028. She doesn’t know what event that is yet, whether it’s the 200m freestyle or the 200m backstroke or the 800m, as she is using Singapore as the test run for the 800m.
“Right now I’m really just trying to cede this new challenge and see if I can do five events individually and see how well I can do in them and see if I can manage it as well,” McIntosh said in her press conference. “LA is always in the back of my mind and my goal for there is to do five events so doing that run-through now three years out is definitely something that will give me lots of confidence as we get closer and closer to LA.”
The matchup with Ledecky, who broke her own world record earlier this year for the first time since 2016 and is swimming at the top of her game, was hard to pass up.
“Any time I get to race Katie, it’s a learning experience and it’s always a good race,” McIntosh said. “I’m really excited to match up with her in Singapore in the 400m free and 800m, which I’ve never done the 800m on the world level before so that’ll be lots of fun. Any time I get to race Katie, it’s lots of fun and I learn so much about myself and we bring the best out of each other for sure.
“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.”
Her coach Fred Vergnoux, who famously guided the likes of Mireia Belmonte to 200m butterfly Olympic gold in 2016, has expressed the possibility of McIntosh breaking 8:00, which very well could happen with Ledecky alongside her. At this point, any wild and blasphemous prediction could come true with McIntosh in the water.
“Even right after in my post-race interview (at Trials), I said the middle 400 I was in nowhere’s land,” McIntosh said of her 800m freestyle when she went 8:05. “I didn’t really know where I was. Having someone that is going around the same pace beside me will give you that adrenaline rush.”
McIntosh has expanded what was thought to be possible in the sport of swimming. It’s hard to believe with four Olympic medals on two trips to the Games and three world records to her name that she is still only 18-years-old. More world records are expected in her future, as many have predicted she’s not done getting faster.
“I think the goal is to always be faster and that’s how I approach every day in training,” McIntosh said. “I think the fun part of the sport is not knowing how fast you’re going to swim at a meet and those unknowns are really fun.”
Image Source: Summer McIntosh of Canada competes in the Women’s 200m Individual Medley Heats on Day 17 of the World Aquatics Championships – Singapore 2025 (Adam Pretty/Getty Images)
McIntosh’s campaign at these championships begins with the 200m IM and 400m freestyle on day one. Despite being the world record holder and the reigning Olympic champion, the 200m IM is a new event for her at the championships, having bypassed the event at the 2022 and 2023 World Championships in favor of the 400m free. This year, she will take on both, with the 400m being another event she has yet to conquer internationally, winning silver at the 2022 Worlds and 2024 Olympics, as well as fourth at the 2023 Worlds.
“Going into past big meets, I haven’t had the confidence in my training and in my freestyle in general, technique wise and endurance wise that I have now, especially with Fred,” McIntosh said of the 400m freestyle. “He has really pushed me to the next level in my freestyle and having endurance to finish an 800m has definitely also helped my 400m freestyle so I’m super pumped for the 400m freestyle and I’m also really excited to see how I manage doing the double.”
Image Source: Summer McIntosh competes in the Women’s 400m Freestyle Heats on Day 17 on 2025 World Aquatics Championships in Singapore (Adam Pretty/Getty Images)
McIntosh is the clear favorite for the 400m freestyle, sitting two seconds ahead of Ledecky in the world rankings. She has an opportunity to win five individual gold medals at these championships, something only Mr. Phelps has done in Melbourne 2007. Ledecky has the most for any woman in a single championship when she won four in Kazan 2015.
McIntosh is aware of the history at stake but not putting pressure on it.
“I have expectations and goals which is to get as many golds as possible,” McIntosh said. “A good motivation for me is to put on a show, that is the energy I channeled going into the Olympic Games and keeping the sport exciting and fun. The goal is always to win and be at my best and reach my full potential, whatever that looks like, I’m not sure yet.”