(D)：Difending Champion
| Date | Championships | Course | Venue | Champion | |
| 5/7 – 5/10 |  |
Asia-Pacific Open Diamond Golf Cup 2020 (cancelled) | Sohbu Country Club Sobu Course | CHIBA | Yosuke Asaji（D） |
| Unfixed | 62nd 2020 Japan Women’s Amateur Golf Championship (cancelled) | Daisen Golf Club | TOTTORI | Mao Saigo（D） | |
| Unfixed | 105th 2020 Japan Amateur Golf Championship (cancelled) | Ohtone Country Club West Course | IBARAKI | Taichi Kimura（D） | |
| 8/19 – 8/21 | 26th 2020 Japan Junior Golf Championship Boy’s 15-17 Division (cancelled) | Hidaka Country Club East/West Course | SAITAMA | Haruto Toge（D） | |
| 8/19 – 8/21 | 26th 2020 Japan Junior Golf Championship Boy’s 12-14 Division (cancelled) | Hidaka Country Club East/West Course | SAITAMA | Misaki Yoshizawa（D） | |
| 8/19 – 8/21 | 26th 2020 Japan Junior Golf Championship Girl’s 15-17 Division (cancelled) | Tokyo Golf Club | SAITAMA | Tsubasa Kajitani（D） | |
| 8/19 – 8/21 | 26th 2020 Japan Junior Golf Championship Girl’s Division 12-14 (cancelled) | Tokyo Golf Club | SAITAMA | Karen Hokazono（D） | |
| 8/25 – 8/28 | 74th 2020 Japan Collegiate Golf Championship (cancelled) | Aichi Country Club | AICHI | Kosuke Sunagawa（D） | |
| 8/26 – 8/28 | 57th 2020 Japan Women’s Collegiate Golf Championship (cancelled) | Aichi Country Club | AICHI | Hinano Hoshikawa（D） | |
| 9/17 – 9/20 |  |
30th 2020 Japan Senior Open Golf Championship | Naruo Golf Club | HYOGO | Akira Teranishi |
| 10/1 – 10/4 |  |
53rd 2020 Japan Women’s Open Golf Championship | The Classic Golf Club King/Queen Course | FUKUOKA | Erika Hara |
| 10/15 – 10/18 |  |
85th 2020 Japan Open Golf Championship | Murasaki Country Club Sumire Course | CHIBA | Yuki Inamori |
| 10/28 – 10/30 | 42nd 2020 Japan Senior Golf Championship (cancelled) | Tosa Country Club Katsurahama/Muroto Course | KOCHI | Hideki Tachi（D） | |
| 10/29 – 10/30 | 28th 2020 Japan Women’s Senior Golf Championship (cancelled) | Hodogaya Country Club | KANAGAWA | Junka Hayashi（D） | |
| 11/5 – 11/6 | 27th 2020 Japan Mid-Senior Golf Championship (cancelled) | JFE Setonaikai Golf Club | OKAYAMA | Toru Sasaki（D） | |
| 11/12 – 11/13 | 27th 2020 Japan Grand-Senior Golf Championship (cancelled) | Tarumi Golf Club | HYOGO | Masaaki Ueki（D） | |
| 11/18 – 11/20 | 25th 2020 Japan Mid-Amateur Golf Championship (cancelled) | Spring Field Golf Club | GIFU | Akio Mizukami（D） | |
| 11/19 – 11/20 | 25th 2020 Japan Women’s Mid-Amateur Golf Championship (cancelled) | Fukuoka Country Club | FUKUOKA | Kaori Matsuyama（D） | |
| 12/1 | 11th 2020 J-sys Golf Tournament JGA Cup Men’s (cancelled) | Ono Golf Club | HYOGO | Takeshi Fujiwara（D） | |
| 12/1 | 11th 2020 J-sys Golf Tournament JGA Cup Women’s (cancelled) | Ono Golf Club | HYOGO | Kyoko Nakatani（D） | |
| Date | Championships | Course | Venue | |
| 9/27 | 14th 2020 All Japan Elementary Student Golf Tournament Boy’s Division (cancelled) | Three Lakes Country Club | MIE | |
| 9/27 | 14th 2020 All Japan Elementary Student Golf Tournament Girl’s Division (cancelled) | Three Lakes Country Club | MIE | |