| ITF W25 Limassol | 11/30 08:00 | 26 | [296] Sofia Costoulas v Hanne Vandewinkel [343] | 7-5,6-1 | |
| ITF W25 Limassol | 11/29 08:00 | 25 | Sofia Costoulas v Angelina Wirges | 3-6,7-6,6-0 | |
| ITF W25 Limassol | 11/26 09:00 | 29 | [330] Hanne Vandewinkel v Sofia Costoulas [291] | 6-2,4-6,6-4 | |
| ITF W25 Limassol | 11/25 08:00 | 28 | [291] Sofia Costoulas v Anastasia Zakharova [192] | 6-2,7-5 | |
| ITF W25 Limassol | 11/24 12:10 | 27 | Sofia Costoulas v Rebecca Munk Mortensen | 6-3,6-2 | |
| ITF W25 Limassol | 11/23 08:00 | 26 | [291] Sofia Costoulas v Polina Iatcenko [356] | 6-4,6-0 | |
| ITF W25 Limassol | 11/22 08:00 | 25 | [291] Sofia Costoulas v Weronika Falkowska [333] | 6-3,6-2 | |
| ITF W40 Pétange | 11/17 16:00 | 27 | [101] Oceane Dodin v Sofia Costoulas [297] | 6-2,7-5 | |
| ITF W40 Pétange | 11/16 08:50 | 26 | Sofia Costoulas v Veronika Podrez | 6-3,3-6,6-1 | |
| ITF W40 Pétange | 11/15 12:55 | 25 | [267] Antonia Ruzic v Sofia Costoulas [297] | 4-6,7-6,1-6 | |
| ITF W60 Nantes | 10/30 16:05 | 25 | [297] Sofia Costoulas v Natalija Stevanovic [185] | 2-6,7-6,4-6 | |
| ITF W80 Poitiers | 10/26 12:20 | 26 | [111] Anna-Lena Friedsam v Sofia Costoulas [296] | 6-3,6-2 | |
| ITF W80 Poitiers | 10/24 08:30 | 25 | Marine Szostak v Sofia Costoulas | 1-6,7-6,2-6 | |
| ITF W60 Hamburg | 10/17 09:10 | 25 | Alevtina Ibragimova v Sofia Costoulas | 2-6,6-4,6-4 | |
| ITF W40 Quinta do Lago | 10/11 09:00 | 25 | [131] Olivia Gadecki v Sofia Costoulas [281] | 7-6,6-1 | |
| ITF W25 Santarém | 09/27 13:15 | 25 | Laura Pigossi v Sofia Costoulas | Cancelled | |
| ITF W25 Santarém | 09/27 09:00 | 25 | Alina Charaeva v Sofia Costoulas | 6-2,3-6,6-4 | |
| ITF W25 Ceuta | 09/23 12:05 | 28 | [291] Sofia Costoulas v Aliona Falei [340] | 6-3,4-6,0-6 | |
| ITF W25 Ceuta | 09/22 09:30 | 27 | Kira Pavlova v Sofia Costoulas | 5-7,3-6 | |
| ITF W25 Ceuta | 09/21 08:00 | 26 | Anastasiia Grechkina v Sofia Costoulas | 4-6,2-6 | |
| ITF W25 Ceuta | 09/19 13:30 | 25 | Arlinda Rushiti v Sofia Costoulas | 4-6,6-1,2-6 | |
| ITF W25 Leiria | 09/14 10:00 | 26 | [288] Sofia Costoulas v Eva Guerrero Alvarez [434] | 4-6,6-3,3-6 | |
| ITF W25 Leiria | 09/13 13:15 | 25 | Sofia Costoulas v Ranah Akua Stoiber | 6-3,6-0 | |
| ITF W25 Verbier | 08/23 08:55 | 25 | [299] Sofia Costoulas v Berta Bonardi [419] | 7-5,5-7,3-6 | |
| ITF W25 Bistrița | 08/18 11:20 | 27 | [299] Sofia Costoulas v Ilinca D Amariei [438] | 6-7,3-6 | |
| ITF W25 Bistrița | 08/17 13:05 | 26 | Sofia Costoulas v Jessica Pieri | 7-6,6-4 | |
| ITF W25 Bistrița | 08/15 12:15 | 25 | Sofia Costoulas v Briana Szabo | 6-3,6-1 | |
| ITF W60 Hechingen | 08/03 12:05 | 26 | [141] Brenda Fruhvirtova v Sofia Costoulas [307] | 6-3,6-2 | |
| ITF W60 Hechingen | 08/01 16:45 | 25 | Sofia Costoulas v Stephanie Wagner | 6-2,6-3 | |
| ITF W40 Porto | 07/19 18:35 | 25 | Sofia Costoulas v Daria Khomutsianskaya | 3-6,6-7 |
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.