| Copa Billie Jean King | 04/13 19:05 | 64 | Emma Navarro v Sofia Costoulas | CANC | |
| Copa Billie Jean King | 04/12 22:00 | 64 | [5] Jessica Pegula v Sofia Costoulas [279] | 4-6,6-2,6-3 | |
| ITF W50 Kashiwa | 04/05 03:15 | 27 | [356] Ya-Hsuan Lee v Sofia Costoulas [285] | 6-1,6-2 | |
| ITF W50 Kashiwa | 04/04 03:30 | 26 | [285] Sofia Costoulas v Priscilla Hon [189] | 6-2,6-2 | |
| ITF W50 Kashiwa | 04/02 03:40 | 25 | [285] Sofia Costoulas v Sohyun Park [299] | 6-2,6-2 | |
| ITF W50 Kofu | 03/28 03:10 | 26 | [286] Sofia Costoulas v Destanee Aiava [196] | 3-6,4-6 | |
| ITF W50 Kofu | 03/27 04:00 | 25 | Sofia Costoulas v Rin Nakagawara | 6-1,6-2 | |
| ITF W15 Hinode | 03/23 01:00 | 28 | Sofia Costoulas v Maegan Manasse | 2-6,3-6 | |
| ITF W15 Hinode | 03/22 00:55 | 27 | Sofia Costoulas v Dabin Kim | 3-6,6-3,6-0 | |
| ITF W15 Hinode | 03/21 04:20 | 26 | Sofia Costoulas v Kisa Yoshioka | 6-0,6-3 | |
| ITF W15 Hinode | 03/20 05:00 | 25 | Sofia Costoulas v Yui Chikaraishi | 6-0,6-2 | |
| ITF W35 Santo Domingo | 03/13 13:25 | 25 | [279] Sofia Costoulas v Maria F H Gonzalez [205] | 6-0,3-6,3-6 |
Sofia Costoulas (born 2 April 2005) is a Belgian tennis player.
Costoulas has a Greek–Congolese father and a Belgian mother.
Costoulas has a career-high singles ranking by the Women's Tennis Association (WTA) of 248 and a best doubles ranking of 229.
On the ITF Junior Circuit, she had a career-high combined ranking of No. 2, achieved on 18 April 2022. She lost the girls' singles final of the 2022 Australian Open to Petra Marčinko. She had already reached the Wimbledon junior doubles final in 2021.