[2] In June 2021 it was announced that Pagonis was named to Team USA, competing in swimming at the 2020 Summer Paralympics in Tokyo, Japan.

[3][4] At just 17-years-old, Pagonis represented the United States in the women's 400 metre freestyle S11 event at the 2020 Summer Paralympics where she set the S11 class world record in the preliminary heat with a time of 4:58.40.

[6][7] She competed in the women's 200 metre individual medley SM11 event where she set an American record with a time of 2:45:61 and won a bronze medal.

[9] She made her World Championships debut on June 15, 2022, and won a gold medal in the 200 metre individual medley SM11 event with a time of 2:49.73.

[10] Pagonis underwent shoulder surgery in June 2023, and returned to swimming and training for the 2024 Summer Paralympics in December 2023.