This impressive peak dominates the landscape south of Dolgellau. From a climber’s point of view there are a number of intriguing crags cast around its various cwms and ridges. The climbing is all traditional and mostly multi-pitch; although a variety of single pitch routes exist. Best and most frequented of the main crags is Cyfrwy, with its namesake Arete, a classic Diff/V Diff. The rock here is occasionally suspect and runners are not too abundant, nonetheless the popular routes give good outings with plenty of mountain crag atmosphere.
The vast, sprawling Craig Cau has a wealth of routes throughout the grade range from Sev to fierce Extremes. The main drawback is the extensive vegetation and often difficult approaches. Indeed the ability to cope with steep vegetated terrain is something of a must hereabouts. It is possible, with some careful planning and intimate crag knowledge, to abseil in and do the cleaner upper pitches of certain routes.
Most of the crags are situated quite high on the mountain, consequently the best season to plan a visit is the summer. Most of the crags are quite slow to dry after rain, but popular routes such as Cyfrwy Arête are less affected by drainage.
The main Cadair Idris crags can be reached from the road in an hour or more. For Cyfrwy approach from the Gwernan Lake Hotel side of the mountain, and for Craig Cau approach from the A487 at the Idris Gates car park.