| Climber Name | # Ascents Recorded | Notes |
|---|---|---|
| Jon Cort | 1 | |
| Jon Egil Auestad | 1 | |
| Jon Kannapell | 1 | |
| Jon Lincoln | 1 | |
| Jonny Hork | 1 | |
| Jordana Agapito | 1 | |
| Jorge Totelegu | 1 | |
| Joseph Brunhuber | 1 |
Pioneer of winter mountaineering and one of the best Austrian alpinists of the 1930s. Brunhuber was the usual partner of Fritz Kasparek but was unable to accompany him on the first ascent of the 1938 route on the Eiger north face, his place being taken by Heinrich Harrer. Spent the war as instructor in the military mountaineering school and helped Jewish refugees escape Nazi Austria. In later years he worked as ski instructor and mountain equipment shop owner. References |
| Josephine Scarr | 1 |
English-born Australian climber, mountaineer, author and archeologist. First female climbing instructor at Plas Y Brenin
References[1] https://www.outsidersstore.com/blogs/blog/tea-biscuits-with-jo-scarr |
| Josh Cullen | 1 | |
| Josh Levin | 1 | |
| Josh Rexroad | 1 | |
| Josh Rundle | 1 | |
| Juan Antonio Jimenez Portillo | 1 | |
| Julia Fiser | 1 | |
| Julia Kruder | 1 | |
| Julian Saunders | 1 | |
| Julie Pearson | 1 | |
| Juliet Hammer | 1 | |
| Junta Sekiguchi | 1 |