Stadium: Court 3 Round: 26 Ground: Hardcourt outdoor
| ITF W15 Monastir WD | 2021/05/14 12:30 | Proctor/Ulyashchenko v Koshiishi/Sakatsume | 6-1,6-4 |
| ITF W15 Monastir WD | 2021/05/12 13:15 | Koshiishi/Sakatsume v Hosogi/Sukhotina | 6-1,6-3 |
| ITF W15 Monastir WD | 2021/05/06 14:30 | Raggi/Scholl v Koshiishi/Sakatsume | 2-6,6-4,11-9 |
| ITF W15 Monastir WD | 2021/05/05 13:10 | Koshiishi/Sakatsume v Le Bihan/Noel | 6-4,7-5 |
| ITF W15 Monastir WD | 2021/04/28 12:50 | Le Bihan/Noel v Koshiishi/Sakatsume | 6-2,6-4 |
| ITF W15 Antalya WD | 2021/02/19 09:00 | Koshiishi/Sakatsume v Gonzalez/Lizarazo | 1-6,7-5,6-10 |
| ITF W15 Antalya WD | 2021/02/09 13:50 | Bosio/Martins v Koshiishi/Sakatsume | 6-1,6-2 |
| ITF W15 Antalya WD | 2021/02/04 11:30 | Arshinkova/Topalova v Koshiishi/Sakatsume | 6-2,7-6 |