| ITF W25 Verbier | 08/23 08:55 | 25 | [299] Costoulas, Sofia v Bonardi, Berta [419] | 7-5,5-7,3-6 | |
| ITF W25 Bistrita | 08/18 11:20 | 27 | [299] Costoulas, Sofia v 아마리에이, 일린카 달리나 [438] | 6-7,3-6 | |
| ITF W25 Bistrita | 08/17 13:05 | 26 | Costoulas, Sofia v 피에리, 제시카 | 7-6,6-4 | |
| ITF W25 Bistrita | 08/15 12:15 | 25 | Costoulas, Sofia v Szabo, Briana | 6-3,6-1 | |
| ITF W60 Hechingen | 08/03 12:05 | 26 | [141] Fruhvirtova, Brenda v Costoulas, Sofia [307] | 6-3,6-2 | |
| ITF W60 Hechingen | 08/01 16:45 | 25 | Costoulas, Sofia v 와그너, 스테파니 | 6-2,6-3 | |
| ITF W40 Porto | 07/19 18:35 | 25 | Costoulas, Sofia v Khomutsianskaya, Daria | 3-6,6-7 | |
| ITF W25 Corroios-Seixal | 07/12 10:00 | 25 | 팔레이, 알리오나 v Costoulas, Sofia | 6-4,2-6,6-3 | |
| ITF W25 Tainan | 06/20 03:40 | 25 | [285] Costoulas, Sofia v 초, 이 첸 [414] | 3-6,4-6 | |
| ITF W25 Tainan | 06/15 04:35 | 26 | [476] 시미즈, 아야노 v Costoulas, Sofia [281] | 6-4,3-6,7-6 | |
| ITF W25 Tainan | 06/14 04:10 | 25 | Imbo Nloga, Samantha v Costoulas, Sofia | 2-6,1-6 | |
| ITF W25 Troisdorf | 05/31 12:20 | 25 | Costoulas, Sofia v Gina M Dittmann | 3-6,6-3,5-7 | |
| ITF W60 Grado | 05/24 11:25 | 26 | [325] Costoulas, Sofia v 밥티스트, 하일레이 [244] | 3-6,2-6 | |
| ITF W60 Grado | 05/23 07:30 | 25 | [338] 시스코바, 안나 v Costoulas, Sofia [325] | 0-6,1-6 | |
| ITF W25 Feld Am See | 05/20 10:05 | 29 | 살덴, 라라 v Costoulas, Sofia | 3-6,1-6 | |
| ITF W25 Feld Am See | 05/19 09:00 | 28 | [326] Costoulas, Sofia v 칼리에바, 엘비나 [243] | 6-2,6-3 | |
| ITF W25 Feld Am See | 05/18 08:00 | 27 | [345] 크왈린스카, 마자 v Costoulas, Sofia [326] | 4-6,4-6 | |
| ITF W25 Feld Am See | 05/17 11:00 | 26 | [367] Kayla Cross v Costoulas, Sofia [326] | 7-5,5-7,3-6 | |
| ITF W25 Feld Am See | 05/17 07:30 | 25 | Koller, Arabella v Costoulas, Sofia | 6-4,4-6,1-6 | |
| ITF W25 Osijek | 04/27 10:40 | 26 | [334] Costoulas, Sofia v 루카스, 테나 [233] | 4-6,1-6 | |
| ITF W25 Osijek | 04/26 09:30 | 25 | [334] Costoulas, Sofia v Avdeeva, Julia [465] | 2-6,6-3,7-6 | |
| ITF W60 Bellinzona | 04/17 12:35 | 24 | [342] 라자로 가르시아, 안드레아 v Costoulas, Sofia [358] | 7-5,6-3 | |
| ITF W25 Santa Margherita | 04/15 11:50 | 28 | [411] 프리사카리우, 안드리아 v Costoulas, Sofia [360] | 6-1,1-6,6-2 | |
| ITF W25 Santa Margherita | 04/14 11:10 | 27 | Costoulas, Sofia v 빌라르도, 페데리카 | 6-4,6-4 | |
| ITF W25 Santa Margherita | 04/13 08:30 | 26 | [301] 파올레티, 마틸드 v Costoulas, Sofia [360] | 1-6,3-6 | |
| ITF W25 Santa Margherita | 04/11 14:15 | 25 | [360] Costoulas, Sofia v 야마자키, 이쿠미 [426] | 7-6,6-2 | |
| ITF W60 Pretoria | 03/16 08:00 | 26 | [192] 오즈, 이페크 v Costoulas, Sofia [347] | 7-6,6-1 | |
| ITF W60 Pretoria | 03/14 09:25 | 25 | [347] Costoulas, Sofia v 엔구이엔 탄, 루시 [378] | 6-3,6-1 | |
| ITF W25 Pretoria | 03/11 08:00 | 28 | [347] Costoulas, Sofia v 베크타스, 에미나 [325] | 3-6,6-4,6-7 | |
| ITF W25 Pretoria | 03/10 08:00 | 27 | [338] 두어스트, 제니 v Costoulas, Sofia [347] | 4-6,3-6 |
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.