Ground: Hardcourt outdoor
| ITF Thailand F9 | 2015/06/21 03:00 | Issei Okamura v Teeradon Tortrakul | 6-7,6-4,6-1 |
| ITF Thailand F9 | 2015/06/14 04:25 | Issei Okamura v Zach Itzstein | 6-3,5-7,5-7 |
| ITF Japan F6 | 2015/06/11 01:00 | Issei Okamura v Duckhee Lee | 1-6,4-6 |
| ITF Japan F6 | 2015/06/09 04:00 | Koichi Sano v Issei Okamura | 2-6,4-6 |
| ITF Japan F6 Qual | 2015/06/08 01:00 | Yuichiro Inui v Issei Okamura | 3-6,1-6 |
| ITF Japan F5 | 2015/06/01 04:10 | Issei Okamura v Ryota Tanuma | 6-7,4-6 |
| ITF Japan F5 | 2015/05/30 01:00 | Issei Okamura v Shota Iino | 6-3,2-6,6-4 |
| ITF Thailand F9 | 2015/05/06 06:35 | Tyler Hochwalt v Issei Okamura | 6-3,1-6,6-2 |
| ITF Thailand F9 | 2015/06/17 03:30 | Ken Onishi v Shuichi Sekiguchi | 3-6,3-6 |
| ITF Thailand F9 | 2015/06/16 05:00 | Zach Itzstein v Ken Onishi | 6-4,2-6,0-6 |
| ITF China F6 | 2015/06/04 02:00 | Ken Onishi v Marcos Giraldi Requena | 4-6,4-6 |
| ITF China F6 | 2015/06/02 06:00 | Ken Onishi v Aoxiong Wang | 7-6,6-4 |
| ITF China F6 | 2015/05/26 02:00 | Ken Onishi v Young Seok Kim | 3-6,5-7 |
| ITF China F6 Qual | 2015/05/24 02:00 | Ken Onishi v Aoran Wang | 6-4,6-4 |
| ITF Thailand F9 | 2015/04/28 05:15 | Christopher O'Connell v Ken Onishi | 7-6,6-2 |
| ITF Thailand F9 | 2015/04/26 06:00 | Chayanon Kaewsuto v Ken Onishi | 6-4,1-6,2-6 |