| Climber Name | # Ascents Recorded | Notes |
|---|---|---|
| Ola Laitinen | 1 | |
| Oliver Chinn | 1 | |
| Oliver Hill | 1 | |
| Oliver Kuang | 1 | |
| Ollie Dreghorn | 1 | |
| Olli-Petteri Manni | 1 | |
| Omar Rose | 1 | |
| Oscar Alexanderson | 1 | |
| Owen Glynne Jones | 1 |
A founding member of the Climbers' Club and a member of it's first committee. Jones died in an accident on the Dent Blanche. References[1] Climbers' Club Journal 1899 Vol. 2 No. 6 (1899) /library/7391/climbers-club-1899-vol.2-no.6-journal |
| Owen Marquez Cellier | 1 | |
| Øystein Andresen | 1 | |
| Øystein Bårdsnes | 1 | |
| Øystein Krydsby Johnsen | 1 | |
| Øyvind Mathiassen | 1 | |
| Paddy Buchan | 1 | |
| Pamela Shanti Pack | 1 | |
| Patrick Olander | 1 | |
| Patrick Pedersen | 1 | |
| Patrik Aufdenblatten | 1 | |
| Paul Bolger | 1 |