Sonia O'Neill

In 2012, O'Neill began attending Niagara University, where she played for the women's soccer team. During her first season, she tore the cruciate ligaments in her knee. In 2014, she moved to the University of North Florida to join their women's soccer team. She did not play in 2014 due to a season-ending knee injury. In 2015, she was named to the Atlantic Sun Conference Academic Honour Roll.

In May 2017, O'Neill joined Swedish Elitettan club Husqvarna FF, scoring two goals in her first match. After two months, she had to return to Canada due to visa issues. In February 2018, she moved to Roma CF to play in the Italian Serie B. In September 2018, she signed with Pink Bari in the Serie A. In August 2019, she briefly played with Croatian club ŽNK Split at the 2019–20 UEFA Women's Champions League. In September 2019, O'Neill signed with French Division 1 Féminine club Fleury. In January 2020, she joined Scottish Women's Premier League club Rangers. In 2021, she returned to play for Split again. In September 2022, she joined German club Turbine Potsdam. In July 2023, she announced she was taking a step away from the game for a period for her mental health due to the toxic nature of women's football. In August 2023, she signed with English club London City Lionesses in the second tier Women's Championship. In December 2023, she took another break from the game due to her pregnancy, missing the remainder of the season. In December 2024, O'Neill joined Calgary Wild ahead of the inaugural Northern Super League season. On April 16, 2025, she started in the league's inaugural game, a 1–0 loss to Vancouver Rise FC.

O'Neill was eligible to represent for Canada, Venezuela, or Italy at international level. In late October 2019, she was called up to the Venezuelan national team for the first time. She made her debut on 8 April 2021 in a friendly against Argentina.

O'Neill played youth soccer with North York Hearts-Azzurri and Master's FA.