The 25-year-old Tasmania native retires as one of the most prolific distance swimmers of all time.

“It’s a tough one, but one that I’m really happy with,” Titmus shared in an Instagram video post on Thursday.

“I’ve always loved swimming … but I guess I’ve taken this time away from the sport and realised some things in my life that have always been important to me are just a little bit more important to me now than swimming.”

A 2025 Laureus Comeback Athlete of the Year nominee, Titmus was diagnosed with a tumour in her ovary in September 2023. Following a successful surgery, Titmus recovered in time and set the women’s 200m freestyle World Record at 1:52.23 in the lead-up to the Paris 2024 Olympic Games.

In the French capital, Titmus became the first woman in nearly a century to defend the 400m freestyle title in a competition billed before the Games as the “Race of the Century”  against her great American rival Katie Ledecky and Canadian Summer McIntosh. She collected another three medals at Paris 2024, including gold in the 4x200m freestyle relay. With the 400m freestyle win in Paris, Titmus became the first Australian woman since Dawn Fraser won back-to-back gold medals in the same event in 1964.

Titmus called the health scare a “turning point” in her retirement announcement post.

“A turning point for me, or a time when a switch was flicked, was in the lead-up to the Paris Games. I went through some health challenges, which, quite frankly, really rocked me mentally.

“It probably was the first time that I considered some things outside of swimming.

“Delving more into those health challenges, I’ve really had to look within and think about what’s most important to me and beyond swimming, I’ve always had goals in my personal life, but swimming has always been most important up until this point and I’ve just realised that those goals and what I want in my future is now more important to me.”

“But more than anything, I’m excited for what’s next.”

Athletes and Coaches Reflect on What Titmus Meant to the Swimming Community

Twenty-five members of the Australian Swimming national team are currently competing in the 2025 Swimming World Cup tour, which is currently in Westmont, Illinois, following the opening meet of the series in Carmel, Indiana. The World Cup series will conclude in Toronto, Canada on 25 October.

World Aquatics caught up with the Australian Dolphins swimmers and national team coaches in Westmont.

Lani Pallister, Australian Dolphins Teammate

As an athlete, Ariarne did incredible things for the sport and for Australia. It's exciting for her that she's chosen to retire, move on, and do something different in life. She's done incredible things for swimming and set the standard in Australia and internationally. “Arnie” and I have raced many times in the past six years, for the most part and for both of us, there were lots of highs and lows. She made me a better athlete for it, and I'm really grateful for that. 

Mollie O’Callaghan, Australian Dolphins Teammate

Ariarne played a massive role in Australian swimming and dominated the 200m free and the 400m free events. She really set high standards, and she's shown us that there's so much that we can do as a team and as a nation. I had the privilege of training alongside her at St. Peter's Western, as we had the same coach. It was just amazing to watch her dominate in training sessions and do the same in her racing. 

She evolved Australia’s 4x200 m freestyle relay. She contributed so much to the nation's success, and I think, as a person, she's shown that, with grit and determination, you can get it. I think she's really set the standard high, especially for me in the 200 freestyle. To race alongside her and watch her grow as an athlete and to keep dominating was such a privilege.

I recall the 4x200m freestyle relay at the 2023 World Championships, like I was leading off the relay and she was going last. We were just trying to fire her up behind the blocks: "Come on, Arni”, you are number one in the world in the 200m free, you've got the fastest split ever, and you've got this. We were trying to gear her up, and obviously, there was a little bit of swearing and all that added into it. To see her on the block and in the zone is quite cool. What we saw from her in the last leg of that relay was just incredible; she swam a 1:52.41, which was just amazing. The following year, at the Olympics, witnessing what she accomplished as a person was even more inspiring.

Kaylee McKeown, Australian Dolphins Teammate

I can really understand and sympathise with the fact that she's accomplished everything that she's ever dreamed of and even more than she dreamed of. Having that feeling and finishing on that note, I think, is such a surreal and special thing to do, just knowing when to call things quit. I think deep down, she's probably known for a while. 

She will have a legacy in the sport for a very long time. She's a legend. We actually made our first senior team together, so watching her video, I teared up a little bit just because we've shared so many memories together, I've watched her win her first Olympic gold medal, and she's watched me win mine. I think just along the track, we've always had that secret support for one another, although we swim in completely different events. 

Obviously, we were teammates when on international trips, but early on, we were roommates at one of our first staging camps. I believe that I was 15 and she was 16. We were both so timid and shy, but we were both out there having the best times. I think one of my fondest memories with her is just not really giving a damn about anything to anyone, and just swimming because she loved it. 

Sam Short, Australian Dolphins Teammate

Obviously, she enjoyed a phenomenal career. I think she won everything that was to win and captured all the world records there were to get, and she beat the great American swimmer Katie Ledecky. Growing up as a swimmer, I looked up to Ariarne when she won those Olympic medals in 2021. Just watching Ariarne made me want to be part of it. Her retirement obviously leaves a big hole in the Australian team that needs to be filled. We've got great talent coming through but losing someone who is a multiple world record holder and Olympic champion, it may take some time to do that, because she is one of the greats. Some of the stuff I saw her do in training was just out of this world. Like, she’d keep up with the elite guys in the group. There's no surprise to me why she won everything she did.

Mel Marshall, Australia Dolphins Coach

I think one of the most beautiful things about her career is the fascinating races and spectacles that she's been able to put together and deliver under what is probably the most significant pressure. I've loved watching that partnership between her and Dean. It's been a beautiful partnership, and we all witnessed some of the most epic races that we've all been lucky enough to watch because of her presence in them.

She will win in whatever she does next because she's developed a great character and a great mindset. Whoever is lucky enough to work with her in the future will be illuminated by her presence. I think those in the sport should be incredibly thankful, either as a competitor, as a spectator, or as a coach on the poolside, I will always be incredibly thankful for her contributions.

Rohan Taylor, Australia Dolphins Coach

We're losing a really stable athlete on the Australian team who has really provided leadership throughout her career. We need to fill the gap, but first, I want to celebrate what she's done and her legacy for Australian Swimming. 

Ariarne has been such a consistent performer in the 400m freestyle, unbeaten from 2019 to 2024. The way she competes and performs, and her influence throughout her career, was unique. She is a very authentic, genuine person and was a great teammate to those who have been able to be on any team with her.

I appreciate the opportunity to reflect on her career, but more importantly,  I have the opportunity to wish her all the best going forward. Everybody's career comes to an end at some point, and we'll move on. Ariarne will always be a Dolphin, and she will always be a part of the Australian Swimming family. 

The competition results and medals won were something that everyone saw. I was fortunate to be on deck with Ariarne and Dean Boxall (her swim coach), and I saw firsthand their remarkable partnership. Being able to watch some of the training sessions she delivered was like seeing things I had never seen before. I was impressed with her ability to produce performances in training and under really heavy conditions with a lot of expectations. That's why she was so good in competitions, because of what she was able to do in training. She excelled at how she prepared herself, and that would be her thing.