Canadian teenager Summer McIntosh smashes Ariane Titmus’ 400m world record

Australia’s swimmers have been warned there’s a dangerous predator lurking in the waters, with Canadian teenager Summer McIntosh obliterating one of Ariarne Titmus’ world records.

Australian Olympic swimming champion Ariarne Titmus has been given a brutal reminder of the enormous challenge she faces staying at the top after Canadian teenage sensation Summer McIntosh obliterated her most prized world record.

Currently on a year off after successfully defending her 400 metres freestyle at last year’s Paris Olympics, Titmus will have to bide her time and wait until she gets back into the water before she can even think about regaining her No. 1 ranking after McIntosh crushed her world record with an incredible display of speed and stamina.

Already unrivalled as the world’s best female swimmer, the 18-year-old McIntosh wiped more than a second of Titmus’ old record of 3:55.38, which she set at the 2023 world championships, when she glided to the wall in an astonishing time of 3:54. 18 at the Canadian world championship trials on Sunday.

“Going into tonight, I knew that my training has been really good these past few months and I knew I could do something special,” McIntosh said.

“So being able to input my training in doing that, I mean, I didn’t think my training would be 54.1, but I’m really happy with that overall.”

SUMMER MCINTOSH!!!!

NEW WORLD RECORD!!!!

3:54.18 400 FREESTYLE!!!

pic.twitter.com/TriF9W5nDw

— Kyle Sockwell (@kylesockwell) June 8, 2025

Titmus has never lost to McIntosh in any of their head-to-head races over 400m and got the better of her to win the gold in Paris last year and also in Tokyo in 2021.

But the Canadian, who is six years younger, is far and away her biggest threat to joining the Olympic immortals by winning three in a row at the next Olympics at Los Angeles in 2028.

Titmus’ strength has always been her electrifying late bursts but McIntosh, who won three individual gold medals in Paris while still just 17, has now worked out how to beat her. She already had superior early speed but can come home as quickly as the Terminator.

And she did it easily in the end. Her split times were: 27.22, 29.73, 29.61, 29.86, 29.62, 29.61, 29.47, 29.06, as she became the first woman to break 30 seconds for every single lap of the race.

“To be honest, I didn’t just really feel a lot of pain in that,” McIntosh said.

“I think I just felt so strong throughout and that’s never been the case in the 400m freestyle for me. That last 100m, I’m always really, really hurting. But I flipped at the 200m and I was just cruising.

“I knew that I was having a strong swim. I can tell by the crowd and the way they were cheering that I was probably close to the world record. So I really tried to push that last part for them.”

Ariarne Titmus held off Summer McIntosh (left) and Katie Ledecky (right) at the Olympics. Picture: Maddie Meyer/Getty Images

With Titmus skipping this year’s world titles in Singapore, McIntosh will be odds-on to win the gold and possibly go even faster but that’s just the start of her ambitious plans.

A versatile talent, she is targeting five individual gold medals in Singapore and possibly more at LA in 2028, when she will still only be 21 and rising to her peak.

A big-stage performer, her latest achievement happened in the same Canadian pool where Australia’s Kieren Perkins broke two world records (800m and 1500m) in the same 1500m event at the 1994 Commonwealth Games.

“There’s a bunch of records up there,” McIntosh replied when asked about the famous names on the pool’s honour board.

“It’s really cool to see. And knowing the history, I always try to become a part of that. I think I did that tonight so overall, I’m really happy.”

The last time Titmus lost her 400m world record to McIntosh she went back to work, trained the house down and regained it a year later. But losing it a second time will still come as a disappointment to the Aussie champion because it’s one of her most cherished accomplishments.

Titmus had already achieved something everyone thought was impossible when she eclipsed the seemingly impenetrable world record of 3:56.46 held by American superstar Katie Ledecky from 2016 to 2022.

But Titmus’ new record didn’t last long and has since been lowered on another three separate occasions, once by herself and now twice by McIntosh.

With four Olympic gold medals in her collection - three from individual events and one from a relay - Titmus is already one of the all time greats of the sport but after busting her gut to beat Ledecky, her most dangerous predator is the younger rival still lurking in the waters.

Not content with what she’s already achieved in the pool, McIntosh is still hungry for more.

Later this year she will change coaches to join Bob Bowman, who oversaw the careers of Michael Phelps and Leon Marchand, and is targeting the same events as Australia’s best in the years ahead.

Originally published as Canadian teenager Summer McIntosh smashes Ariane Titmus’ 400m world record