Stadium: Court A5 Round: 62 Ground: Synthetic outdoor
| ITF Women Tsukuba | 2018/08/20 01:00 | Nagi Hanatani v Ayumi Koshiishi | 6-2,7-6 |
| ITF Women Tsukuba | 2018/08/19 00:30 | Ange Oby Kajuru v Ayumi Koshiishi | 1-6,4-6 |
| ITF Women Nonthaburi | 2018/08/11 03:00 | Ayumi Koshiishi v Punnin Kovapitukted | 2-6,2-6 |
| ITF Women Nonthaburi | 2018/08/06 05:15 | Lou Brouleau v Ayumi Koshiishi | 6-1,6-3 |
| ITF Women Nonthaburi | 2018/08/05 04:15 | Michika Ozeki v Ayumi Koshiishi | 7-6,5-7,3-6 |
| ITF Women Nonthaburi | 2018/08/04 06:10 | Jia Qi Ren v Ayumi Koshiishi | 1-6,6-1,2-6 |
| ITF Women Taipei | 2018/07/26 02:00 | Ayumi Koshiishi v Hua-Chen Lee | 3-6,0-6 |
| ITF Women Taipei | 2018/07/24 03:45 | Ting-Pei Chang v Ayumi Koshiishi | 2-6,1-6 |
| ITF Women Hammamet | 2018/06/11 09:00 | Yuka Hosoki v Ayaka Ozeki | 6-0,7-6 |
| ITF Women Hammamet | 2018/06/10 08:00 | Ayaka Ozeki v Niditra Rajmohan | 6-1,6-0 |
| ITF Women Hammamet | 2018/06/05 10:35 | Ayaka Ozeki v Eliessa Vanlangendonck | 2-6,3-6 |
| ITF Women Hammamet | 2018/06/03 12:00 | Ayaka Ozeki v Sarra Ata | 7-5,6-1 |
| ITF Women Hamamatsu Qual | 2017/10/14 01:00 | Ayaka Ozeki v Sae Haraguchi | 2-6,6-4,3-6 |
| ITF Women Kyoto | 2017/09/04 01:00 | Ayaka Ozeki v Momoko Nishio | 6-4,1-6,6-7 |
| ITF Women Nanao Qual | 2017/08/27 04:00 | Aiko Yoshitomi v Ayaka Ozeki | 2-6,6-2,7-6 |
| ITF Women Focsani Qual | 2017/07/02 06:00 | Selma Stefania Cadar v Ayaka Ozeki | 6-2,7-6 |