Leah O’Brien

BIOGRAPHY

What an incredible rise it has been for Perth sprinter Leah O’Brien, now our fastest under-18 sprinter in history, she pushed Torrie Lewis in the Australian 100m final placed second just 0.004 second behind. Still only 17, she is selected for her Australian team debut in the 4x100m relay for the Tokyo World Championships.

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Leah O’Brien’s journey in athletics started age 8 when some family friends were impressed with her running at a school carnival and encouraged her parents to take her along to Little Athletics.  “I joined UWA Little Athletics Club and instantly fell in love with the sport. I enjoyed chatting and having fun with my friends between events, and I quickly realised that sprints were for me when I won the state championships in my very first season.”

At her first Australian Championships in 2021 she won the U14 100m and 200m. Her PBs that season, as a 13-year-old, were 12.19 and 25.12. She has gone on to win seven National titles. In a sign of things to come, in 2024 aged just 16, she made the open National 100m final. She had been making consistent progression over the years: 100m 12.19 (2021, 13y), 12.04 (2022, 14y), 11.82 (2023, 15y), 11.76/11.56w (2024, 16y).

But Leah’s 2025 campaign has been incredible. At 200m she took over a second from her PB to clock 23.37 in the U18 Nationals. This was a turning point for Leah: “I went in with low expectations after a rough run in the heats, but I chose not to let that define or affect me. I came off the bend in the lead, thinking, “Oh my god, I’m winning!” It was such a surreal moment, proving to myself that anything is possible and to never limit what I can achieve. That race kicked off my most successful Nationals campaign yet.”

But it would be in the 100m where Leah would made the most impact. After a couple of quick windy assisted times during the season, including a best of 11.33w, she ran PBs of 11.50, then 11.46 and a stunning 11.14 while winning the Australian under-18 title.

The time destroyed the 47-year-old Australian U18 100m record of 11.20 set by Raelene Boyle at Mexico in 1968 when she placed 4th in the Olympic final.

Summary of the statistics on Leah’s phenomenal 11.14 performance:

-Australian U18 record

-#9 U18 World All-time list

-#2 AUS U20 all-time

-#4 AUS all-time

-2025 World U18 leader (@ 4 Sept 2025)

But Leah was not done at the Australian championships when four days later she contested the open 100m title, running 11.31, 11.29 and 11.24 through the rounds. The medals were incredibly close: 1st Torrie Lewis 11.24, 2nd Leah O’Brien 11.24 and 3rd Bree Masters 11.25. The difference between Torrie and Leah was 11.24236 to 11.24240 – that is 0.0004 seconds.

Memorable sporting achievement: Most memorable race was the U18 200m final at Nationals this year. I went in with low expectations after a rough run in the heats, but I chose not to let that define or affect me. I came off the bend in the lead, thinking, “Oh my god, I’m winning!” It was such a surreal moment, proving to myself that anything is possible and to never limit what I can achieve. That race kicked off my most successful Nationals campaign yet. My proudest moment, however, was breaking the U18 Women’s 100m National record. Doing it at home, in front of family and friends had made it extra special. I had believed I was capable of running that time but thought it be in my senior career. It was a moment I’ll never forget…

Hero: the other female sprinters running on the world stage…Most influential person in career:
Her family and coach. My coach, Braiden Clarke, has trained me for over five years. He’s taught me the importance of patience in my results and self-belief while coaching me on transitioning smoothly from juniors into senior competition. My family has supported me unconditionally from day one. My mum, dad, and brothers are always cheering me on and believing in me, no matter what…Advice to your young self: Be patient and don’t rush things; Trust the process—improvement takes time, but it’s always worth it…Hobbies: baking, beach & travelling… Sporting ambition: short term – I want to consistently run 11.1–11.3 seconds in the 100m and continue improving my 200m to be competitive at the Open level. Long-term, my goal is to represent Australia at the Olympics in an individual sprint event and hopefully make it to the semi-finals or further. I also want to achieve something no Australian female sprinter has done before, to run under 11 seconds in the 100m…Education: In 2025 Year 12 student at Perth College Anglican School for Girls, Subjects – English, Mathematics Applications, Human Biology and Psychology…Biggest challenge faced: dealing with shin splints last season. It impacted my training and limited my ability to compete at my best at Nationals. I had to pull out of the 200m and focus solely on the 100m. I knew I was capable of more, and it was tough to accept. However, that experience taught me resilience and discipline. It motivated me to work even harder this year and focus on all the “1 percenters” my coach talks about. Looking back, I’m almost grateful for the setback, it helped me grow mentally and physically, and pushed me in training to focus and work harder…Interesting facts: born in New Jersey, USA; is a triplet with all brothers; family heritage mother is Australian, and father is Irish.

@ 4 Sept 2025 david.tarbotton@athletics.org.au