Maria Xiao

In 2010, Xiao represented Portugal at the 2010 Summer Youth Olympics in Singapore. She participated in the women's singles and the mixed doubles with Emilen Vanrossomme of Belgium. She advanced from round one of the women's singles after winning two of her three matches. However, she was eliminated in round two after losing two of her three matches. In the mixed doubles, Xiao and Vanrossomme finished runners-up in their group and advanced to round two where they lost to eventual bronze medalists Gu Yuting of China and Adem Hmam of Tunisia.

Xiao was Portugal's reserve player for the 2012 Summer Olympics in London, England, United Kingdom.

She represented Portugal before 2012 and Spain afterwards.

Xiao qualified to represent Spain at the delayed 2020 Summer Olympics in Tokyo, Japan where she participated in the women's singles. In the first round, she defeated Anastassiya Lavrova of Kazakhstan 11–9 11–6 11–4 7–11 11–3. She followed that up with a 7–11 11–6 11–8 11–8 8–11 11–9 against Minnie Soo of Hong Kong. Her run came to an end in the third round where she lost 8–11 12–10 11–5 11–2 11–4 against Feng Tianwei of Singapore.