| Mami Koyama 小山真実 | |
| Position: | Forward |
| Height Ft: | 5 |
| Height In: | 11 |
| Weight Lb: | 148 |
| League: | FIBA 3X3 |
| Team: | Tokyo Dime |
| Number: | 10 |
| Nationality: |  Japanese |
| Birth Date: | 1995 5, mf=yes |
| Birth Place: | Chiba, Chiba |
| Highschool: |
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| Career Start: | 2014 |
| Years1: | 2014-17 |
| Team1: | JX-Eneos Sunflowers [1] |
| Years2: | 2017-19 |
| Team2: | Haneda Vickies |
| Years3: | 2019-present |
| Team3: | Tokyo Dime |
is a Japanese professional basketball player who plays for Tokyo Dime.[2] She also plays for Japan women's national 3x3 team. She brought the U23 national team to a silver medal at the FIBA 3x3 Under-23 World Cup in Xi'an .