the source for mountain bike trails worldwide

Afan Argoed Has the Rocky Mountain sponsored 20km singletrack Penhydd, Trail, and the highly technical trail known as 'he Wall'
Cym Carn Has the purpose build Twrch Trail and a visitors centre. It’s a stones throw from the M4 and only a few miles from the English border so it’s dead easy to get to.

Oh and there's a nice short DH course with road access to ride back up.

Coed y Brenin The heart of Welsh mountain biking with the famous Red Bull and MBR trails plus the Karrimor loop’s 38km of technical singletrack. It’s a training ground for world class racers