Ordered by the number of ascents recorded.
| Climb Name | Type | Grade | # Ascents Recorded | Notes | Exclude Reason |
|---|---|---|---|---|---|
| One Inch Punch | Trad climb | E9 | 1 | ||
| One in the Swarm | Trad climb | E8 | 1 | ||
| One Man and His Dogmas | Trad climb | E5 | 1 | ||
| One Step Beyond | Trad climb | E6 | 1 | ||
| Only Human | Trad climb | E5 | 1 | ||
| Open Book | Trad climb | E1 | 1 |
The first route to be graded 5.9 in the US. |
|
| Opening gambit | Trad climb | HVS | 1 |
One of the first routes on slate, up the huge tottering back wall of Twll Mawr, the climb has been substantially altered by rockfall since Joe Brown’s first ascent and is now graded XS. An adventure strictly for connoisseurs. |
|
| Ophir Broke | Trad climb | E5 | 1 | ||
| Orange Crush | Trad climb | E6 | 1 | ||
| Orcrist | Trad climb | E5 | 1 |
Named after the "goblin cleaving" sword from Lord of the Rings. References |
|
| Original Route | Trad climb | VD | 1 |
E. A. Baker:
|
|
| Original Route | Trad climb | HVS | 1 | ||
| Our Father | Trad climb | E4 | 1 |
Probably one of the hardest free climbs in the UK when Tom Proctor made the first ascent. So named because Geoff Birtles spoke the Lord's Prayer before attempting to second Tom Proctor on the first ascent. |
|
| Our Kid | Trad climb | E4 | 1 | ||
| Out for Blood | Trad climb | E9 | 1 |
The pitches breakdown as E8 6c in to E9 7a, a substantial outing! |
|
| Out of the Dark | Trad climb | E6 | 1 | ||
| Overhanging Bastion (pre-rockfall) | Trad climb | VS | 1 | ||
| Overlooked | Trad climb | E7 | 1 | ||
| Over The Moors Direct | Trad climb | E7 | 1 | ||
| Owd Gadgee | Trad climb | E2 | 1 |