The phrase “surf’s up” has a whole new meaning along the jagged coastline of Pembrokeshire. While most people are content to look at the stunning surroundings from the comforts of dry land, I chose a different view, deciding to pit myself against the sea as it crashed into the rough shore.

Coasteering is a fast-growing activity in which seemingly intelligent people kit themselves out in heavy wetsuits, buoyancy aids, crash helmets and old trainers, and then step into a foaming sea. It is a muscle-tightening mix of rock climbing, orienteering, cliff diving and swimming as you seek out routes over shale and through caves, scramble up precipices, then jump back down.

I’ve seen what the sea can do to vessels caught in its maw. Images of dashed ships filled my head as I pulled on my wetsuit — there were definitely some second thoughts running around up there. But 15 American exchange students, 14 of them women, were up for the challenge, and if they could do it, so could I.

Our guides, Mark and Mick, from Preseli Venture, ran over the safety procedures. It didn’t sound too bad until the bit about ocean swells. “They can help you or hinder you,” Mick said. “Timed right and they are like a hand gently nudging you out of the sea. Timed wrong, and you will scrape your hands to the bone on barnacles.”

Once in the water, though, it was an exhilarating experience. The frantic action of the sea and constant scrambling had every muscle working.

We swam through swirling channels, skated on seaweedcovered rocks, scaled serrated rock faces and meandered through huge caves. Then we climbed up a rock precipice and jumped back in. By the time we finished I felt as if I’d been through a washing machine — a little beaten up, but a lot cleaner.

After that, the thought of mountain biking sounded like a doddle — until I saw the new Mojo Mountain downhill run at Cwmcarn, near Newport. The circuit is the first world-class downhill mountain bike-run in the UK, built not only to provide British racers with a proper circuit but also to protect the local environment.

The 1.2-mile trail is open to all, but is definitely not for the beginner. As I stood at the top looking down I thought there was no way it could be ridden. It was just too steep and too rocky. Enter 24-year-old Rowan Sorrell, a local downhill mountain bike racer.

Sorrell took off ahead of me at speed, jumping every bulge and bump, and landing easily. My descent was much less dramatic. After a couple of cartwheels I walked my bike down, dignity intact.

To round off my trip I tried rock climbing in the hills around Capel Curig in Snowdonia National Park.

“North Wales has the whole spectrum of climbing,” said Ben Law, a guide for Plas-y-Brenin, the National Mountain Centre. “There are even great climbs along the sea cliffs.”

I came to Wales to challenge myself. But I got as much enjoyment out of driving through the Brecon Beacons and into northern Snowdonia as I did doing the coasteering, biking and climbing. With its varied landscape, Wales has everything to offer for a physically challenging holiday.

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