Ordered by the number of climbs recorded. About slate.
| Crag | Location | # Climbs |
|---|---|---|
| Rainbow Slab | United Kingdom / Wales / Caernarfon | 19 |
| Vivian Quarry | United Kingdom / Wales / Gwynedd / Caernarfon | 15 |
| Forest Rock | United Kingdom / England / Leicestershire / Loughborough | 12 |
| Gideon Quarries | United Kingdom / Wales / Caernarfon | 12 |
| Twll Mawr | United Kingdom / Wales / Caernarfon | 10 |
| Serengeti | United Kingdom / Wales / Caernarfon | 9 |
| Australia | United Kingdom / Wales / Caernarfon | 5 |
| California | United Kingdom / Wales / Caernarfon | 5 |
| The Lost World | United Kingdom / Wales / Caernarfon | 4 |
| Carn Vellan | United Kingdom / England / Penzance | 4 |
| The Brand | United Kingdom / England / Loughborough | 3 |
| Bus Stop Quarry | United Kingdom / Wales / Caernarfon | 2 |
| Dali's Hole | United Kingdom / Wales / Caernarfon | 2 |
| Hodge Close Quarry | United Kingdom / England / Westmorland and Furness / Coniston | 2 |
| Zawn Duel and Carn Gloose Area | United Kingdom / England / Saint Ives | 2 |
| Nant Peris Quarry | United Kingdom / Wales / Caernarfon | 2 |
| Breakwater Quarry | United Kingdom / Wales / Holyhead | 1 |
| Never Never Land | United Kingdom / Wales / Caernarfon | 1 |
| Zennor Cliff | United Kingdom / England / Saint Ives | 1 |
| Thrang Quarry | United Kingdom / England / Westmorland and Furness / Ambleside | 1 |