Mollie O'Callaghan


Mollie Grace O'Callaghan is an Australian swimmer and the reigning Olympic champion in the 200 m freestyle. She was the 2023 world champion in the women's 100m and 200m freestyle individual events, and part of the world champion and Australian women's relay teams together with mixed relay team. She currently holds the world record in the women's individual 200m freestyle.
O'Callaghan also won two gold and one bronze medals at the 2020 Summer Olympics as a heats swimmer in relay events and gold medal in the 200 m freestyle and 4 × 100 metre freestyle relay at the 2024 Summer Olympics.
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Career

2020 Summer Olympics

O'Callaghan swam for the Australian team in the preliminaries of all three women's relays at the 2020 Summer Olympics in Tokyo, receiving two gold medals and one bronze for her contribution. Swimming the 1st leg for Australia in the heats of the 4 × 100 metre freestyle relay, she posted a time of 53.08 and received a gold medal after the Australian team won the final.
In the 4 × 200 metre freestyle relay preliminaries, O'Callaghan swam a junior world record of 1:55.11 when swimming the lead off leg. Her time would have placed her fifth in the 200 metre freestyle final. However, because the Australian coaches had previously decided to use four fresh swimmers in the final, O'Callaghan was not selected for the final where Australia finished third.
In a heat of the 4 × 100 metre medley relay, O'Callaghan again posted a competitive time; her anchor leg split was 52.35, only 0.24 seconds slower than the fastest freestyle split in the final by Cate Campbell.

2022 World Aquatics Championships

After her teammate, Shayna Jack, broke her hand from slipping over in the warm-up area, O'Callaghan swam the final leg for the Australian team only 90 minutes after her semi-final in the 100m freestyle, finishing with the silver medal 2.41 seconds behind the American team. Her 100m freestyle semi-final notably saw her register a second 50m split of 26.43, which became the quickest second 50m split in history after turning the wall at the 50-metre mark in last place.

2023 World Aquatics Championships

At the 2023 World Aquatics Championships, O'Callaghan was a world champion in five events.
O'Callaghan won the women's 100m freestyle in 52.16, after qualifying in second place, and the women's 200m freestyle in a world record time of 1:52.85 after qualifying in third place. She was the first woman to win both of these events in a single world championship.
O'Callaghan was also part of three champion relay teams, each of which set a world-record time: the women's freestyle relay; the women's freestyle relay; and the mixed freestyle relay.

2024 Summer Olympics

The final major event for O'Callaghan before the Olympics was the Australian Olympic trials, held in Brisbane, with a highly anticipated duel in the 200m freestyle between herself and her training mate Ariarne Titmus. O'Callaghan notably held four of the fastest seven times in the 200m freestyle before trials took place. Before the 200m freestyle final, O'Callaghan suffered a panic attack, struggling to breathe and was "up at night crying before the race". Throughout the race, O'Callaghan was not able to spot Titmus, with her goggles fogging throughout the duel and said she was only "focused on myself". With fellow training mate, Titmus, both of them swam the two fastest times in 200-metre freestyle history, with Titmus beating O'Callaghan by 0.25 seconds; with splits between them for each lap being 0.05, 0.20 and 0.16 seconds respectively. O'Callaghan was pleased that she could now "fly under the radar" heading into the Olympics, with Titmus taking the world record and "the pressure off me". The fast race for all the Australian women competing made the Australian team the favourites for the relay gold medal, while O'Callaghan and Titmus became favourites to win gold in the individual event.
After the overwhelm of nerves before the 200-metre freestyle final, O'Callaghan's nerves dissipated before the finals of the 100-metre freestyle, she was the only competitor to swim faster in the final compared to her qualifying time, she was able to place first and earn the first-seeded quota spot for the highly competitive Australian spot. Although O'Callaghan was not happy with her time, she was pleased to have an opportunity to compete as an individual swimmer, after being a relay swimmer in Tokyo.
On the first night of swimming in Paris, O'Callaghan competed in the final of the 4x100m freestyle, with the Australian team tipped to win the event for the fourth consecutive Olympic Games. Joining O'Callaghan in the final included fellow relay gold medallists in Tokyo, Emma McKeon and Meg Harris, and Olympic debutant Shayna Jack. O'Callaghan started the relay for the team, turning in fourth during the first half of her leg, then taking the team into the lead on her second half of her leg with the rest of the team maintaining their lead, setting an Olympic record in the process.
In one of the most anticipated races of the games, O'Callaghan once again went head-to-head with compatriot and training mate, Titmus, in the 200m freestyle, weeks after both women set the two fastest times in history at the Australian Olympic trials. The race would also mark O'Callaghan's first Olympic final in an individual event. Similarly to the 2023 world championships, O'Callaghan again beat Titmus on the world stage, winning gold in the 200m freestyle final, with Titmus, the defending Olympic champion achieving silver. While visibly shaking with nerves on the starting block in comparison to Titmus' calmness, O'Callaghan, who was fifth at the first 50-metres, used her trademark second-half race speed and underwater work to gain on Titmus and bronze-medallist Siobhán Haughey, to win by a half-a-second, only gaining the lead on the final lap. O'Callaghan also surpassed Titmus' Olympic record from 2021 in the process, and prevented Titmus from becoming the first woman to defend a 200m freestyle title in Olympic history. This marked the first time that Australia completed a gold-silver finish in any Olympic event since Ian Thorpe and Grant Hackett in the 400m freestyle in 2004. The historical moment was acknowledged by both O'Callaghan and Titmus who walked out of the pool holding hands above their heads, and O'Callaghan famously inviting Titmus to the top step to sing the national anthem alongside her during the medal ceremony. When asked about the decision to invite Titmus to share the top podium step with her, O'Callaghan said, "I think, you know, no matter who stands on that podium, if it's a fellow Aussie always invite them up. They're my teammate." O'Callaghan admitted she was "a nervous wreck" and struggled to sleep in the lead-up to the race. She dedicated her victory to her "support team" including her family and her coach, Dean Boxall.
After her victory in the 200m freestyle, this made O'Callaghan a heavy-favourite to complete a historic 100m-200m freestyle double at the Olympics. In the lead-up to the final, O'Callaghan suffered a bout of anxiety and experienced very little sleep, finding it difficult to "get up" and prepare for the race. She found her "lack" speed in comparison to her competitors as an area she was finding a challenge to perfectly execute, which became evident during the final race. Starting on the blocks, noticeably nervous and O'Callaghan would miss the podium completely, losing gold to Sarah Sjöström, placing fourth and completely missing the podium. O'Callaghan's loss in the 100-metre freestyle was considered one of the biggest surprises of the Olympics. O'Callaghan did not have time to rest, with the 4x200-metre freestyle relay taking place the next evening.
With O'Callaghan and Titmus finishing gold-silver in the individual event, this made the Australian team heavy-favourites to win gold in the 4x200-metre freestyle relay, with Lani Pallister and Brianna Throssell joining O'Callaghan and Titmus for the final. O'Callaghan was the first swimmer to go in the relay, maintaining the lead throughout and swimming close to world-record time. Their lead was maintained throughout the entire race, with the American team finishing in silver and the Chinese team awarded bronze. The team finished only 0.58 seconds behind their own world record set at the 2023 world championships. The victory was the first time the Australian team had won the 4x200m freestyle relay since 2008. The win vindicated the Australian team's surprising loss in Tokyo.
After the Olympics, O'Callaghan made the decision to take a hiatus for the rest of the year.

2025 World Aquatics Championships

Due to her hypermobility, O'Callaghan again sustained a dislocated knee injury in January, affecting her training for several months including water-based training. The knee injury occurred on the opposite leg to when her 2023 knee injury occurred and wore a brace to help move the knee back into place. When competing at her first event of the year, the Australian National Championships in April, O'Callaghan described the injury as "like I'm kicking with one leg".
After winning the 200m freestyle title at the Australian Trials in August, O'Callaghan admitted she found the pressure of the "status" as an Olympic champion "really stressful", notably breaking down in tears during her post-race interview, while also elaborating the physical and mental challenges she was facing with her knee injury. Despite setting the fastest time of the year in the 200m freestyle, she felt her swim at trials was "awful".
O'Callaghan's first world title of the championships came at the 4x100m freestyle relay. Leading off the team and swimming a time of 52.79, which maintained Australia's dominance in the event extending back to the 2018 Commonwealth Games with her swim being pivotal in maintaining Australia's lead. With teammate and fellow Olympic gold medallist Meg Harris, along with two debutants in Milla Jansen and Olivia Wunsch, the team, according to O'Callaghan, were "very nervous" before the race start. Notably their American rivals, who were suffering from gastroenteritis, saw their anchor, Gretchen Walsh, withdraw before the final.
O'Callaghan was able to defend her 200m freestyle trial, after qualifying third for the final. Keeping up with her traditional strategy of conserving energy for the last half of the race, she swam the first 100m at the same pace as eventual bronze-medallist Claire Weinstein, only to pull away after the halfway point and establish a dominant lead that went unchallenged, winning in 1:53.48. She praised her Australian team, as well as her coaches for providing a "positive environment" and helping her prepare mentally and physically. This world title, her 10th overall, equalled Grant Hackett as second on the all-time world titles list for Australian swimmers, one behind Ian Thorpe.
Just over 24 hours after winning her 200m freestyle title, O'Callaghan entered as Australia's final swimmer in the 4x200m freestyle relay for the first time since 2022, alongside Lani Pallister, Jamie Perkins and Brittany Castelluzzo, matching up O'Callaghan head-to-head against Katie Ledecky. After Castelluzzo managed to move the Australian team to the lead by only 0.39 seconds ahead of the American's, once O'Callaghan dived in for her leg, she able to maintain Australia's lead, beating Ledecky to the wall by 0.66 seconds. This marked O'Callaghan's third gold medal of the championships and 11th gold medal overall, surpassing Hackett and equalling the Australian record held by Thorpe. When asked about her equalling Thorpe's record, O'Callaghan replied, that although it was "a hot topic", she wasn't considering the thought of achieving it, stating her "rollercoaster" preparation leading into the world championships. After her gold medal in the 4x200m freestyle relay, O'Callaghan had a chance to overtake Thorpe's record if she were to win the 100m freestyle with the final taking place the next day.
Entering as the two-time world champion in the event, O'Callaghan was tipped podium in the event and potentially put her surprise defeat at the 2024 Olympics behind her, with Torri Huske, who had swum the fastest time in the world that year, struggling with illness. Despite the opportunity to make history, O'Callaghan achieved the silver medal, while the gold went to defending world champion Marrit Steenbergen, finishing 0.12 behind Steenbergen. O'Callaghan admitted after she completed the race that fatigue from her race program, which was one of the biggest in the Australian team, had set in and she felt "very tired" after being the only swimmer from the 4x200m freestyle relay the previous evening that also competed in the final tonight. She also was "grateful" for the podium place, pointing towards her disrupted preparations before the world championships and that she "had to pull my shit together as best I could."

Career best times

Long course metres (50 m pool)

EventTimeMeetLocationDateNotes
50 m freestyle24.492024 Australian Swimming TrialsBrisbane15 June 2024
100 m freestyle52.08r2023 World Aquatics ChampionshipsFukuoka23 July 2023
200 m freestyle1:52.482024 Australian Swimming TrialsBrisbane26 July 2023
400 m freestyle4:07.212023 NSW State Open ChampionshipsSydney11 March 2023
50 m backstroke27.162024 Australian ChampionshipsSydney19 April 2024
100 m backstroke57.882024 Australian Swimming TrialsBrisbane11 June 2024
200 m backstroke2:08.482022 Australian ChampionshipsAdelaide21 May 2022
50 m butterfly27.72Queensland ChampionshipsBrisbane11 December 2023
100 m butterfly58.98Queensland ChampionshipsBrisbane11 December 2023
200 m butterfly2:13.74Queensland ChampionshipsBrisbane12 December 2023

Short course metres (25 m pool)

EventTimeMeetLocationDateNotes
50 m freestyle23.812025 World Aquatics Swimming World CupWestmont17 October 2025
100 m freestyle50.822025 World Aquatics Swimming World CupToronto25 October 2025
200 m freestyle1:49.362025 World Aquatics Swimming World CupToronto24 October 2025WR
50 m backstroke25.422025 World Aquatics Swimming World CupToronto23 October 2025
100 m backstroke55.622022 FINA World Swimming Championships (25 m)Melbourne14 December 2022
200 m backstroke2:05.45McDonald's Queensland ChampionshipsBrisbane25 September 2020
50 m butterfly27.87State Teams ChampionshipsCanberra4 October 2019

World records

Long course metres

split 52.03 ; with Jack Cartwright, Kyle Chalmers, Madison Wilson

split 1:54.80 ; with Madison Wilson, Kiah Melverton, Ariarne Titmus

split 52.08 ; with Shayna Jack, Meg Harris, Emma McKeon

split 1:53.66 ; with Shayna Jack, Brianna Throssell, Ariarne Titmus

split 51.71 ; with Jack Cartwright, Kyle Chalmers, Shayna Jack

Short course metres

split 52.19 ; with Madison Wilson, Meg Harris, Emma McKeon

split 1:52.83, with Madison Wilson, Leah Neale, Lani Pallister

split 25.49 ; with Chelsea Hodges, Emma McKeon, Madison Wilson

Olympic records

Long course metres

split 52.24 ; with Shayna Jack, Emma McKeon, Meg Harris

split 1:53.52 with Lani Pallister, Brianna Throssell, Ariarne Titmus

Honours