The Beast of Bryn begins on the rugby field at Bryn Rugby & Social Club, located in Bryn, near Port Talbot. From there, participants head onto hilly trails within Afan Argoed and Afan Forest Park. This UK Athletics race offers two primary distances: a shorter option of approximately 6.5 miles (10.5km) with around 288 metres of elevation gain, and a longer option of about 10.5 miles (17km) with roughly 556 metres of climbing. The event welcomes both novice and seasoned trail runners, though its significant ascents present a true off-road test rather than a fast, flat race.
The courses traverse mountain terrain above the village, with the longer route featuring nearly double the climb of the shorter one. BRAG, the Bryn Residents Action Group, initiated the race in 2011. Following a hiatus and a period under external management, BRAG now operates it as a not-for-profit community initiative. The rugby club serves as the Race Headquarters. A Mini Beast mile is available for children and teenagers up to 18 years old. The event has also been chosen to host the Welsh Trail Running Championships for Master Age Groups.