At a glance
Wales's first mountain bike trail (1994) — 26 km red-grade singletrack at Coed y Brenin forest park, 8 miles north of Dolgellau on the A470. Full trail network from easy to black grade, café, bike hire on site. LL40 2HZ.
About the Marin Trail at Coed y Brenin
Coed y Brenin — the King's Forest — is a large Forestry Wales-managed forest park on the A470 between Dolgellau and Trawsfynydd in southern Snowdonia. In 1994 it became the birthplace of purpose-built mountain biking in Wales when the Marin Trail opened — a 26 km red-grade singletrack circuit through ancient oak woodland and conifer plantation, developed in partnership with the Californian bike brand Marin. The trail established a template that transformed Wales into one of the world's leading mountain biking destinations.
The Marin Trail threads through varied terrain: tight singletrack through the oak woodland floor, rocky ridge sections with open views, technical rooted descents, and fast open forest road links. Total elevation gain is around 700 metres across the circuit — it is a genuine all-day ride for most people. Since 1994 the trail network at Coed y Brenin has expanded to include trails at all grades, from easy family forest road routes to the Beast of Brenin (38 km black grade — one of the most demanding in Wales). Bike hire, including e-bikes, is available at the Visitor Centre.
The forest itself is worth visiting on foot — the Afon Eden and the Afon Mawddach run through the park, and there are waymarked walking routes to waterfalls including Rhaeadr Ddu (Black Falls). The Mawddach Trail traffic-free cycleway begins in Dolgellau, 8 miles south, and connects to the wider cycling network of the Cambrian region.
Find it on the map
Frequently asked questions
The Marin Trail is a 26 km red-grade mountain bike trail at <span lang="cy">Coed y Brenin</span> forest park, 8 miles north of Dolgellau on the A470. Opened in 1994, it was the first purpose-built mountain bike trail in Wales and one of the first in the UK — named after a partnership with the Californian bike brand Marin. It established the template for purpose-built trail riding in Britain, and <span lang="cy">Coed y Brenin</span> has since developed a full network of trails from easy green-grade family rides to extreme black-grade descents.
The Marin Trail is graded red — the UK mountain biking grading for intermediate to advanced trails. It involves sustained singletrack, rooted and rocky sections, some technical descents, and a total elevation gain of around 700 metres across the 26 km circuit. Fit cyclists with off-road experience will find it enjoyable but challenging; beginners should start with the blue-grade Temtiog or one of the forest road routes. The Visitor Centre has trail maps with full gradient and technical information.
<span lang="cy">Coed y Brenin</span> has developed into a full mountain bike resort with trails at all grades. In addition to the Marin Trail (red, 26 km), there are: the Temtiog (blue, 19 km — good for developing riders); the Tarw (red, 30 km — longer and more sustained than the Marin); the Beast of Brenin (black, 38 km — one of the most demanding in Wales); and several easier forest road and family routes. Bike hire is available from the Visitor Centre, including e-bikes.
<span lang="cy">Coed y Brenin</span> is a good family destination, though the mountain bike trails are not suitable for young children. The Visitor Centre has a café, toilets, and bike hire. The adjacent forest has waymarked walking trails and an easy cycling route on forest roads that is appropriate for families with young children on bikes. Older children (10+) who are confident cyclists can attempt the blue-grade Temtiog with supervision. The forest itself — ancient oak woodland with the Afon Eden running through it — is beautiful and worth exploring on foot.
<span lang="cy">Coed y Brenin</span> Visitor Centre is on the A470 approximately 8 miles north of Dolgellau. There is a pay-and-display car park at the Visitor Centre. By public transport: the X94 bus between Barmouth and Dolgellau passes along the A470 — check the current timetable, as services can be infrequent. Dolgellau town is 8 miles south and has B&Bs and a hostel suitable for cycling breaks. The Mawddach Trail (traffic-free cycle path) runs from Dolgellau to Barmouth and can be combined with a visit to <span lang="cy">Coed y Brenin</span> for a full cycling day.