Stadium: Court 4 Round: 62
| ITF Women Incheon Qual | 2018/05/13 03:30 | Freya Christie v Ayumi Koshiishi | 4-6,2-6 |
| ITF Women Goyang | 2018/05/09 04:55 | Ayumi Koshiishi v Lee, So-Ra | 6-7,3-6 |
| 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 | Yoo, Jin v Ayumi Koshiishi | 3-6,3-6 |
| ITF Women Gifu Qual | 2018/04/29 01:00 | Asano, Yuka 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 |
| Kofu, Singles Qualifying W-WITF-JPN-02A | 2018/03/25 01:00 | Lykina, Ksenia v Ayumi Koshiishi | 7-5,6-7,6-3 |
| Kofu, Singles Qualifying W-WITF-JPN-02A | 2018/03/24 00:30 | Ayumi Koshiishi v Haruna Arakawa | 7-5,6-4 |
| ITF Women Incheon Qual | 2018/05/13 03:30 | Lee, Han Byeol v Kang, Seo-Kyung | 1-6,3-6 |
| ITF Women Goyang | 2018/05/09 01:00 | Kim, Na Ri v Kang, Seo-Kyung | 6-1,0-6,6-4 |
| ITF Women Goyang Qual | 2018/05/08 01:00 | Ahn, Yu Jin v Kang, Seo-Kyung | 4-6,2-6 |
| ITF Women Goyang Qual | 2018/05/07 01:30 | Kang, Seo-Kyung v Schaefer, Dominique | 6-3,3-6,6-4 |
| ITF Women Goyang Qual | 2018/05/06 05:15 | Frahn, Madison v Kang, Seo-Kyung | 4-6,0-6 |
| ITF Women Yeongwol | 2017/09/05 02:00 | Kang, Seo-Kyung v Hsu, Ching Wen | 6-3,2-6,3-6 |
| ITF Women Yeongwol | 2017/08/31 02:50 | Pei-Chi Lee v Kang, Seo-Kyung | 7-6,6-4 |
| ITF Women Yeongwol | 2017/08/30 06:10 | Walters, Alexandra v Kang, Seo-Kyung | 3-6,5-7 |