Stadium: Court 3 Round: 25
| ITF Women Goyang Qual | 2018/05/08 05:05 | Yexin Ma v Ayumi Koshiishi | 4-6,3-6 |
| ITF Women Goyang Qual | 2018/05/07 03:30 | Jin Yoo v Ayumi Koshiishi | 3-6,3-6 |
| ITF Women Gifu Qual | 2018/04/29 01:00 | Yuka Asano v Ayumi Koshiishi | 3-6,1-6 |
| ITF Women Osaka Qual | 2018/04/07 01:30 | Ayumi Koshiishi v Akiko Omae | 3-6,2-6 |
| ITF Women Kofu Qual | 2018/03/25 01:00 | Ksenia Lykina v Ayumi Koshiishi | 7-5,6-7,6-3 |
| ITF Women Kofu Qual | 2018/03/24 00:30 | Ayumi Koshiishi v Haruna Arakawa | 7-5,6-4 |
| ITF Women Nishi-Tama | 2018/03/17 04:00 | Kei Kato v Ayumi Koshiishi | 7-5,6-4 |
| ITF Women Toyota Qual | 2018/03/10 01:00 | Ji-Hee Choi v Ayumi Koshiishi | 4-6,6-3,6-2 |
| ITF Women Goyang Qual | 2018/05/08 01:00 | Eunhye Lee v So-Ra Lee | 4-6,2-6 |
| ITF Women Goyang Qual | 2018/05/07 02:30 | Sung Hee Kim v So-Ra Lee | 5-7,2-6 |
| ITF Women Gifu Qual | 2018/04/30 02:30 | Kyoka Okamura v So-Ra Lee | 7-5,1-6,6-2 |
| ITF Women Gifu Qual | 2018/04/29 05:20 | So-Ra Lee v Ramu Ueda | 6-4,6-3 |
| ITF Women Nishi-Tama | 2018/03/25 02:00 | So-Ra Lee v Na Ri Kim | 6-3,2-6,7-5 |
| ITF Women Nishi-Tama | 2018/03/24 02:00 | So-Ra Lee v Dabin Kim | 7-6,6-7,6-3 |
| ITF Women Nishi-Tama | 2018/03/23 01:00 | Ayaka Okuno v So-Ra Lee | 3-6,4-6 |
| ITF Women Nishi-Tama | 2018/03/20 06:15 | Michiru Furuya v So-Ra Lee | 7-5,6-7,4-6 |