(D)：Difending Champion
| Date | Championships | Course | Venue | Champion | |
| 5/12 – 5/13 | 13th 2005 Japan Women’s Senior Golf Championship | Hiroshima Country Club Hachihonmatsu Course | HIROSHIMA | Keiko Hayashi | |
| 6/21 – 6/25 | 47th 2005 Japan Women’s Amateur Golf Championship | Sapporo Golf Club Yuni Course | HOKKAIDO | Shinobu Moromizato | |
| 7/5 – 7/9 | 90th 2005 Japan Amateur Golf Championship | Daisen Golf Club | TOTTORI | Kyung-Tae Kim | |
| 8/17 – 8/19 | 11th 2005 Japan Junior Golf Championship Boy’s 15-17 Division | Kasumigaseki Country Club East Course | SAITAMA | Yuki Ito | |
| 8/18 – 8/19 | 11th 2005 Japan Junior Golf Championship Boy’s 12-14 Division | Kasumigaseki Country Club West Course | SAITAMA | Shunta Maeawakura | |
| 8/18 – 8/19 | 11th 2005 Japan Junior Golf Championship Girl’s 15-17 Division | Kasumigaseki Country Club West Course | SAITAMA | Erina Hara | |
| 8/18 – 8/19 | 11th 2005 Japan Junior Golf Championship Girl’s 12-14 Division | Kasumigaseki Country Club West Course | SAITAMA | Makoto Takemura | |
| 8/23 – 8/26 | 59th 2005 Japan Collegiate Golf Championship | Gifuseki Country Club East Course | GIFU | Yuta Ikeda | |
| 8/24 – 8/26 | 42nd 2005 Japan Women’s Collegiate Golf Championship | Gifuseki Country Club East Course | GIFU | Mika Takushima | |
| 9/29 – 10/2 |  |
38th 2005 Japan Women’s Open Golf Championship | Totsuka Country Club West Course | KANAGAWA | Ai Miyazato |
| 10/13 – 10/16 | |
70th 2005 Japan Open Golf Championship | Hirono Golf Club | HYOGO | Shingo Katayama |
| 10/27 – 10/28 | 12th 2005 Japan Mid-Senior Golf Championship | Ito Golf Club | FUKUOKA | Yukio Imada | |
| 10/27 – 10/28 | 12th 2005 Japan Grand-Senior Golf Championship | Ito Golf Club | FUKUOKA | Hideya Yamamoto | |
| 11/3 – 11/6 | |
15th 2005 Japan Senior Open Golf Championship | Ranzan Country Club | SAITAMA | Tsuneyuki Nakajima |
| 11/9 – 11/11 | 27th 2005 Japan Senior Golf Championship | Kumamoto Kuko Country Club | KUMAMOTO | Kazumasa Yoshimura | |
| 11/16 – 11/18 | 10th 2005 Japan Mid-Amateur Golf Championship | Tokyo Golf Club | SAITAMA | Takayoshi Iseki | |
| 11/17 – 11/18 | 10th 2005 Japan Women’s Mid-Amateur Golf Championship | Minami Aichi Country Club | AICHI | Miyuki Shinotsuka | |