Sofia Costoulas

Costoulas was born in Genk to a Greek-Congolese father and a Belgian mother.^[1] Her father was a professional footballer who played for Sint-Truidense V.V., K. Patro Eisden Maasmechelen, and C.S. Visé.^[2] She began playing tennis at the age of four. She trained at her local club in Genk, the Kim Clijsters Academy, and the Justine Henin Academy.^[1][2]

In July 2021, she and Laura Hietaranta reached the girls' doubles final of Wimbledon, but lost to Kristina Dmitruk and Diana Shnaider.^[3] In September 2021, she reached the girls' singles third round of the US Open.^[4]

In January 2022, she won the J1 Traralgon Tennis International, defeating Kayla Cross in the final.^[4] Later that month, she reached the girls' singles final of the Australian Open, but lost to Petra Marčinko.^[5][6] In April 2022, she won back-to-back J1 titles in Vrsar and Plovdiv.^[1] The following month, she also won the JA International HTV Junior Open in Offenbach am Main.^[7]

In December 2021, she reached back-to-back W15 finals in Monastir.^[8] In February 2022, she reached the semifinals of the W25 Copa Banco in Guayaquil.^[1] In October 2022, she won her first professional doubles title at the W25 tournament in Hua Hin, partnering Punnin Kovapitukted.^[9][10]

In April 2025, she won her biggest title to-date at the W75 Ladies Open Calvi Eaux de Zilia, defeating Tessah Andrianjafitrimo in the final.^[11] The following month, she reached the second round of the qualifying competition of the French Open, but ultimately failed to advance into the main draw.^[12]

Costoulas made her WTA Tour main-draw debut as a qualifier at the 2026 ASB Classic in Auckland and defeated fellow qualifiers Whitney Osuigwe^[13] and Kaitlin Quevedo to reach the quarterfinals,^[14] at which point her run was ended by third seed Iva Jovic.^[15]

Playing alongside Matilde Jorge, she won her first WTA 125 doubles title at the 2026 Oeiras CETO Open, defeating Magali Kempen and Lara Salden in the final.^[16]