Prominent transgender swimmer Lia Thomas has initiated a legal challenge against World Aquatics over its policies that significantly limit transgender athletes’ participation in competitive swimming events, including the Olympics.

The legal dispute, which was lodged with the International Court of Arbitration for Sport in Switzerland in September last year, was discovered by The Telegraph on 26 January.

Thomas’s legal action targets recent regulations imposed by World Aquatics that effectively bar most transgender women and intersex athletes from competing in women’s international swimming competitions.


These rules mandate such athletes to compete in a newly established “open” category instead. Notably, the “open” category was scrapped at the Swimming World Cup held in October 2023 due to a lack of participation.

Under previous guidelines, transgender women were eligible to compete in women’s categories provided they met specific testosterone thresholds. However, a policy change enacted two years ago now disqualifies trans women from women’s elite races if they have undergone any stage of male puberty.

Carlos Sayao, representing Thomas in the legal dispute, criticised the policies as discriminatory, emphasising the heightened vulnerability of trans women to societal violence, abuse, and harassment compared to cisgender women. Sayao argued that World Aquatics’ regulations could inflict significant harm on trans women athletes.

Responding to the controversy, Brent Nowicki, the executive director of World Aquatics, defended the organisation’s gender inclusion policy. Adopted in June 2022, the policy was developed with input from medical and legal experts after consultations with athletes. Nowicki expressed confidence in the fairness of the policy and reiterated World Aquatics’ commitment to safeguarding women’s sports.

Thomas has yet to make public comments on the case.