Brecon to Cardiff Xtreme Ultra Marathon

Brecon to Cardiff Xtreme Ultramarathon

If the Classic Brecon to Cardiff is the gateway to ultra running, the Brecon to Cardiff Xtreme is the beast that waits behind the gate.

This is the "nasty" brother to the original classic. While it shares the same start and finish points, the route is entirely different in character. Instead of following the gentle gradient of the valley floor, the Xtreme heads straight up. It traverses 11 summits, including the highest peaks in South Britain, making it a true mountain ultra.

With nearly 2,700m of elevation in severe winter conditions, this race is not for the faint-hearted. It demands mountain respect, solid navigation skills, and grit. But for those brave enough to toe the line, it offers an adventure through the Welsh mountains that few ever get to see in a single day.

Course

The race begins at 07:00 at the Brecon canal basin. There is no gentle warm-up here. You’ll wind through the town before hitting the mountains immediately, climbing straight to the summit of Pen y Fan, the highest peak in the south of the UK.

From there, the roller-coaster begins. You’ll bag the summits of Cribyn and Fan y Big before plummeting down the technical descent of the Roman Road. Just when you think your legs have recovered, you'll tackle the sharp climb to Twyn Mwyalchod before dropping down to the Pontsticill Reservoir.

Midway through, you’ll reach the indoor checkpoint at Merthyr College (CP3). This is your haven: drop bags, warmth, and food await. It is also a critical decision point; Xtreme runners feeling the strain can choose to drop down to the Classic route here (though you won't get the Xtreme medal!).

While the Classic runners are enjoying a flat run to the finish from Merthyr, your work is far from over. You still have half the elevation left to conquer. The route climbs over Mynydd Aberdare and traverses the historic St Gwynno Forest (keep an eye out for the grave of legendary runner Guto Nyth Brân).

A final ridgeline run over Pen y Foel leads you towards Pontypridd, before one last sting in the tail over Cefn Eglwysilan. The final descent drops you into Nantgarw to cross the finish line, battered, muddy, but undoubtedly proud.

Unlike the fully marked Classic route, the Xtreme is a self-navigation challenge. The route is largely unmarked. You will see some flags where the course briefly joins the Classic route or in dense forestry, but you must rely on your GPS device or map.

Logistics

To keep you focused on just running, the folks at Run Walk Crawl have kept the logistics simple:

1. Park at the Finish: Leave your car at the finish HQ in Nantgarw (Cardiff).
2. Bus to the Start: A bus takes you to Brecon at 05:30 sharp (included in your entry).
3. Drop Bags: Your drop bags are transported to the halfway point in Merthyr so you can restock supplies or change into dry kit.

The B2C Xtreme isn't just a race; it's a winter expedition across the spine of South Wales. If you want to test your limits against the elements and the elevation, this is the one for you! Please visit the official race website for all the latest and up-to-date info, including registration.