| 1. Jornada | 28.02.2021 | Mito HollyHock | - | RB Omiya Ardija | 1:2 | ||||
| 3. Jornada | 24.03.2021 | RB Omiya Ardija | - | Kyoto Sanga FC | 1:2 | ||||
| 5. Jornada | 27.03.2021 | RB Omiya Ardija | - | V-Varen Nagasaki | 4:0 |  |
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| 8. Jornada | 17.04.2021 | RB Omiya Ardija | - | Ehime FC | 0:1 | ||||
| 17. Jornada | 06.06.2021 | Zweigen Kanazawa | - | RB Omiya Ardija | 1:0 | ||||
| 18. Jornada | 13.06.2021 | RB Omiya Ardija | - | Tochigi SC | 1:1 | ||||
| 19. Jornada | 19.06.2021 | Matsumoto Yamaga | - | RB Omiya Ardija | 0:0 | ||||
| 20. Jornada | 27.06.2021 | Renofa Yamaguchi | - | RB Omiya Ardija | 0:1 | ||||
| 21. Jornada | 03.07.2021 | RB Omiya Ardija | - | Montedio Yamagata | 1:3 | ||||
| 23. Jornada | 18.07.2021 | RB Omiya Ardija | - | FC Ryūkyū | 2:2 |
Japón