O'Riain has a career-high singles ranking by the
WTA of 382, reached on 21 October 2002. She also has a career-high WTA doubles ranking of 295, achieved on 22 September 2023. O'Riain has won one singles and seven doubles titles on the
ITF. In September 2002, she won the ITF 25K tennis tournament in
Glasgow, United Kingdom, with partner Yvonne Doyle. Playing for
Ireland at the
Fed Cup, she had a win–loss record of 9–3. She played college tennis at
Harvard University 2005/2006. == ITF Circuit finals ==