| ITF M15 Kashiwa | 2025/04/01 05:41 | Daisuke Sumizawa v Hiromasa Koyama | 6-2,4-5 |
| ITF M15 Tsukuba | 2025/03/26 02:30 | Hiromasa Koyama v Yusuke Takahashi | 3-6,0-6 |
| ITF M15 Nishi-Tokyo | 2025/03/18 04:00 | Hiromasa Koyama v Tai Leonard Sach | 2-6,3-6 |
| ITF M15 Hinode | 2025/03/12 01:00 | Yuta Kawahashi v Hiromasa Koyama | 6-2,6-3 |
| ITF M25 Sapporo | 2024/09/08 01:00 | Kohei Hayashi v Hiromasa Koyama | 6-2,6-4 |
| ITF M25 Sapporo | 2024/09/05 03:10 | Hiromasa Koyama v Keisuke Saitoh | 0-6,6-4,3-6 |
| ITF M25 Sapporo | 2024/09/03 03:00 | Hyeon Chung v Hiromasa Koyama | 5-7,1-6 |
| ITF M15 Tokyo | 2024/07/10 06:15 | Kenta Miyoshi v Hiromasa Koyama | 6-1,6-2 |
| UTR Pro Urayasu | 2025/05/24 00:00 | Toa Maeda v Jaden Dewandaka Tan | 5-7,2-6 |
| UTR Pro Urayasu | 2025/05/23 06:00 | Taichi Wakamatsu v Jaden Dewandaka Tan | 3-6,3-6 |
| UTR Pro Urayasu | 2025/05/22 04:55 | Jaden Dewandaka Tan v Haru Kawanaka | 6-3,6-2 |
| UTR Pro Urayasu | 2025/05/21 01:00 | Jaden Dewandaka Tan v Ryota Tanuma | 5-7,1-6 |
| UTR Pro Urayasu | 2025/05/20 02:35 | Jaden Dewandaka Tan v Taketo Takamisawa | 2-6,3-6 |
| UTR Pro Urayasu | 2025/05/19 02:45 | Jaden Dewandaka Tan v Satoru Nakajima | 7-5,6-2 |
| UTR Pro Kawaguchi | 2025/05/04 01:00 | Kotaro Mochizuki v Jaden Dewandaka Tan | 7-6,4-6,6-1 |
| UTR Pro Kawaguchi | 2025/05/03 04:30 | Jaden Dewandaka Tan v Haruto Ishikawa | 6-3,6-0 |