2025 World Championship Previews: McIntosh To Catch Her White Whale In The 400 Free?

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 400 FREESTYLE

• World Record: 3:54.18 – Summer McIntosh, Canada (2025)
• World Junior Record: 3:56.08– Summer McIntosh, Canada (2023)
• Championship Record: 3:55.38 – Ariarne Titmus, Australia (2023)
• 2023 World Champion – Ariarne Titmus (AUS), 3:55.38
• 2024 Olympic Champion – Ariarne Titmus  (AUS), 3:57.49

Returning Olympic Finalists

• Silver- Summer McIntosh (CAN), Bronze- Katie Ledecky (USA), 4th – Erika Fairweather (NZL), 5th- Isabel Gose (GER), 7th- Maria Fernanda Costa (BRA), 8th- Jamie Perkins (AUS)

In recent years this event has been a battle between the three greatest-ever women to swim the event. Only two of them will take to the water in Singapore, with Ariarne Titmus sitting the post-Olympic year out as she did after Tokyo. Without her, the battle for gold will between Katie Ledecky and Summer McIntosh, although even in what is a resurgent season for the American it is the Canadian that is the overwhelming favourite to finally win her first world title in the event.

Behind that battle will be another one for bronze, with four women holding best times within a second of each other around the four minute mark. With there having been a near monopoly on hardware recently from Titmus, McIntosh and Ledecky there is only one other woman to have won a summer world medal in the last five years in the field – somewhat remarkable considering six of the top eight in history will be in Singapore.

That battle may not be the most enthralling aspect of this race. McIntosh shattered her world record at Canadian trials in 3:54.18, and, although she added time in the event at Worlds in 2023 after setting the Word record at Canadian Trials that year, could do something special here.

A Passing Of The Torch?

McIntosh and Ledecky rank 1st and 2nd in the world this season, however the gap from McIntosh (3:54.18) to Ledecky (3:56.81) is more than two and a half seconds – nearly as much as from Ledecky to #3 Lani Pallister. That speaks volumes about just how dominant a swim that was from the Canadian, with Ledecky’s time standing as her 2nd-fastest ever and ranking within the top-ten all-time.

McIntosh holds all the cards this year. She is the world record holder in both long course and short course – a feat Ledecky never managed – and with no Titmus in the field for the first time since 2022 holds the fastest best time by over two seconds. She has been on a tear in every event she’s touched this season, and hacked nearly two seconds off her previous best at Canadian Trials, dropping from 3:56.08 to 3:54.18. Although she added time from Canadian trials at her last World Championships in 2023 she’s got a much bigger buffer to play with this season.

Katie Ledecky (photo: Jack Spitser)

Ledecky meanwhile is enjoying a resurgent season, swimming her second fastest times ever in both the 400 and 1500 as well as breaking her 800 record that had stood for nearly nine years. She hasn’t missed medalling in this event at any major meet, and she’ll continue that streak this year to take it to 12 years of podiums. It is worth noting that Ledecky did win their one head-to-head this season at the Pro Swim Series. The American does also hold the head-to-head advantage in major finals, beating McIntosh in 2021, 2022 and 2023.

However, with McIntosh’s significantly improved closing speed this season she should have more than enough to take her first world title in the 400 free. Ledecky will not be left behind, but the 18-year-old may be out of reach almost from the start. After claiming the short course world title in December McIntosh will be confident of doing the double the season – with good reason.

An Almighty Scrap For Bronze

Behind the North American duo are a quartet of swimmers with a point to prove. With hardware in short supply recently thanks to the dominance of Ledecky, Titmus and McIntosh this group has only two bronze medals between them from summer world championships or Olympic Games: Erika Fairweather‘s bronze in 2023 and Li Bingjie’s bronze in 2017.

Alongside Lani Pallister (3:59.72, 6th all-time) and Claire Weinstein (4:00.05, 8th all-time), bronze could come from a multitude of angles in this field. Pallister, Bingjie (3:59.99, 7th all-time) and Weinstein have all set their lifetime bests this year, whilst Fairweather set hers just last season. That indicates four women all in top form coming into Singapore.

2022 FINA World Swimming Championships Budapest Budapest, Duna Arena 06/20/22 Photo Fabio Cetti

Fairweather has been the most successful of the four in this event, making the final at every meet since Tokyo and placing no lower than 6th since 2022. However, she does hold the slowest season-best of the quartet at 4:03.06, but does not have the same competition for places that her competitors do, so has not had to be at her best so far this season. She has stood on the podium before and is the only one of this group to have beaten either McIntosh or Ledecky in a major final after taking 3rd ahead of the Canadian swimmer in 2023. After placing 3rd and 4th in the last two summers, she’ll be around there again this year and has room to drop time for third year in a row.

Pallister is having a phenomenal season in distances from the 200 up to the 1500, and will be hoping for a bounceback summer after contracting COVID-19 mid-Olympics. She had not entered the event in Paris after recording her fastest ever in-season time of 4:01.75, one she has smashed in 2025 with her new best of 3:59.72 earlier this year. She finished fourth by less than a tenth of a second back in 2022, but then added three seconds in 2023 to finished 6th. With no Titmus in Singapore, it could well be another Aussie who backs up a strong in-season performance with a medal here

Li has also been having a great season – she set bests in the 200, 400 and 1500 free At Chinese Nationals this year. She has been 4:01-point in three of the last four seasons, but missed the final in Paris last summer in 4:03.96 to mark her third summer in a row where she added time. However after setting a personal best and Asian Record at Chinese Nationals, she is in contention to take her third world medal in the event after doing so in 2017 and 2024.

Weinstein has dropped a huge amount of time this year – already four and a half seconds – but swam her two best times while hot on the heels of Katie Ledecky. Likely more separated from her U.S. teammate in Singapore, she may struggle to replicate her swims from the Pro Swim Series and U.S. Nationals.

The Other Contenders

Germany’s male distance freestylers may be the talk of the town right now, but Isabel Gose is world class on the women’s side as well, following on from the legacy of Sarah Wellbrock (née Köhler). She finished fifth in Paris with a national record of 4:02.14 and has been 4:03.65 this season to rank 9th in the world, and will be a threat to finish in the top six again.

Maria Fernanda Costa (photo: Jack Spitser)

Brazil’s Maria Costa is another returning finalist from Paris and is the South American record holder. She set her best time of 4:02.86 as she finished 4th at the 2024 World Championships, and 4:03 in both the heats and finals at the Olympics, placing 7th. She has only been 4:06 so far this season but with her roster spot assured thanks to her Olympic performance she has not had any reason to be in top form so far.

Jamie Perkins will return for Australia after taking second at their Trials this year, and holds a best time of 4:03.30 from the heats in Paris last summer. She neared that time in Adelaide in 4:04.65 and has sliced nearly a second off her 200 time this year, so should be well in the hunt for a second swim in Singapore.

Yang Peiqi will be the second Chinese swimmer in this event after setting a huge best time of 4:02.53 to qualify at Chinese nationals, a drop of nearly three seconds. She made the final in Doha, finishing 6th, but will need to be faster than the 4:06.82 it took to qualify there to make it back here and with only one swim under 4:05 is not a lock for the final, despite ranking 6th in the world rankings this season.

The Verdict

McIntosh and Ledecky should be the clear 1-2 here, with both in spectacular form this year. McIntosh should have too much for her North American rival this year to seal her first world title in the 400 free, but cannot afford to be complacent.

Lani Pallister has looked fantastic so far this year as well and we think she’ll carry that form. She would need to be on top of her game to keep her local rival Erika Fairweather at bay, but the Kiwi has developed a killer final 100 and will be gunning for her third world medal in a row. She is yet to peak so far this season, and her closing speed may well be to much for the other contenders for bronze.

There should be several returning finalists here, and they will benefit from the experience of knowing what is required to qualify. Even without Titmus in the field it would not be surprising to see at least three swimmers under four minutes once again.

SwimSwam’s Picks

Dark horse: Anastasia Kirpichnikova (France) – Kirpichnikova holds a best of 4:06.26 from the Tokyo Olympics back in 2021, but has shown glimpses that she could be much faster. Although she placed 15th in Paris in 4:10.32, she split 4:07.73 in her silver-medal-winning 1500 and was a hundredth slower than that to win the French Elite championships in 4:07.74 last month. Dropping down into the low four minutes may be a stretch but a finals place could well be within reach.