| ITF W15 Manacor | 01/29 12:10 | 25 | Ayumi Koshiishi v Fiona Ganz | 6-1,6-4 | |
| ITF W15 Manacor | 01/27 09:30 | 44 | Jerricka Boone v Ayumi Koshiishi | 4-6,4-6 | |
| ITF W15 Manacor | 01/26 12:00 | 44 | Nina Ugrelidze v Ayumi Koshiishi | 1-6,2-6 | |
| ITF W15 Manacor | 01/23 15:15 | 25 | Ayumi Koshiishi v Celia C Ruiz | 0-6,6-7 | |
| ITF W15 Manacor | 01/23 12:00 | 44 | Ayumi Koshiishi v Kathleen Kanev | 6-4,6-1 | |
| ITF W15 Manacor | 01/22 16:30 | 44 | Ayumi Koshiishi v Haine Ogata | 6-1,6-3 | |
| ITF W15 Manacor | 01/22 14:00 | 44 | Ayumi Koshiishi v Jillian Louise Roa | 6-2,6-1 | |
| ITF W15 Hua Hin | 10/16 07:10 | 25 | Sakura Hosogi v Ayumi Koshiishi | Retired | |
| ITF W15 Hua Hin | 10/10 03:00 | 26 | Patcharin Cheapchandej v Ayumi Koshiishi | 6-1,6-3 | |
| ITF W15 Hua Hin | 10/09 03:00 | 25 | Ayumi Koshiishi v Mananchaya Sawangkaew | 6-2,6-3 | |
| ITF W25 Kyoto | 09/05 05:30 | 26 | Ayumi Koshiishi v Michika Ozeki | 0-6,3-6 | |
| ITF W25 Kyoto | 09/04 04:25 | 25 | Miharu Imanishi v Ayumi Koshiishi | 3-6,4-6 | |
| ITF W25 Kyoto | 09/02 04:00 | 45 | Ayumi Koshiishi v Utaka Kishigami | 7-5,7-6 | |
| ITF W25 Kyoto | 09/02 00:00 | 45 | Ayumi Koshiishi v Hx Izabella Tan | 6-0,6-1 | |
| ITF W25 Nanao | 08/27 01:00 | 25 | Ayumi Koshiishi v Anri Nagata | 4-6,0-6 | |
| ITF W25 Tsukuba | 08/19 00:30 | 54 | Yui Chikaraishi v Ayumi Koshiishi | 2-6,6-2,10-7 | |
| ITF W25 Nonthaburi | 07/30 02:30 | 54 | Yidi Yang v Ayumi Koshiishi | 6-0,6-2 | |
| ITF W25 Nonthaburi | 07/29 06:20 | 54 | Thasaporn Naklo v Ayumi Koshiishi | 3-6,4-6 | |
| ITF W25 Nonthaburi | 07/23 04:20 | 54 | Ayumi Koshiishi v Michika Ozeki | 2-6,4-6 | |
| ITF W25 Nonthaburi | 07/22 08:00 | 54 | Ho Ching Wu v Ayumi Koshiishi | 3-6,2-6 | |
| ITF W15 Gimcheon | 06/20 01:00 | 26 | Ayumi Koshiishi v Sunam Jeong | 2-6,6-7 | |
| ITF W15 Gimcheon | 06/19 01:00 | 25 | Ayumi Koshiishi v Honoka Kobayashi | 4-6,6-4,6-4 | |
| ITF W15 Gimcheon | 06/14 02:00 | 27 | Ayumi Koshiishi v Misaki Matsuda | 5-7,7-6,3-6 | |
| ITF W15 Gimcheon | 06/13 01:30 | 26 | Ayumi Koshiishi v Shou Na Mu | 7-5,6-3 | |
| ITF W15 Gimcheon | 06/12 01:00 | 25 | Ayumi Koshiishi v Dayeon Back | 7-5,6-2 | |
| ITF W25 Daegu | 06/05 01:00 | 25 | Na-Lae Han v Ayumi Koshiishi | Retired | |
| ITF W25 Daegu | 06/04 01:00 | 54 | Ayumi Koshiishi v So-Ra Lee | 7-5,6-2 | |
| ITF W25 Daegu | 06/03 01:00 | 54 | Ayumi Koshiishi v Yeong Won Jeong | Retired | |
| ITF W25 Luzhou | 05/28 06:15 | 25 | Ayumi Koshiishi v Jessica Ho | 3-6,1-6 | |
| ITF W25 Luzhou | 05/28 02:00 | 54 | Ayumi Koshiishi v WanNing Zhu | 6-0,6-1 |