Pembrokeshire Coast Path in Wales is the only coastal national park in the United Kingdom. The 186-mile hiking path is in the middle of an unforgiving area with cold, six-foot tides smashing against 30-to-100-foot-high rock cliffs. Thanks to rock outcroppings, tidal shifts, and coastal views, adventure-seekers – hikers, surfers, sea kayakers, and rock climbers – visit the remote region around the path year-round. The most unique pursuit in the area, however, is coasteering, a flotation-free pentathlon of beach bouldering, swimming, cliff diving, spelunking, and rock climbing that takes full advantage of the varied terrain here.

TYF, a U.K.-based outfitter, offers half-, full- and two-day coasteering excursions that help you get started with this wild, and potentially dangerous, sport. Along with certified guides, the company supplies wet suits (the water is 30 to 40 F), helmets, and life preservers. Equip yourself and then it's time to climb the rocks, jump into the water, and ride the surf as it pushes you toward the next boulder and cliff along the coast. A highlight of this in-water bouldering is through a narrow rocky crevice known as "the toilet." This nature-built water slide starts with "a wave that funnels through a narrow gap in the rocks," according to our guide, Dean Bird. "Closer to the cliffs it widens, creating a bowl at the back that moves as the water levels rise and fall and the water moves rapidly through its narrowest point," he added. To say the least, it was a thrilling ride.

Throughout the day, our group swam non-stop between cliffs, climbing wet, mossy rock faces as high as 50 feet, and soon we were diving back out to the tumultuous sea. The scrambling around is punctuated by a calm respite, though, in huge, coastal caves that line the coast. Once we were inside the caves, the water smoothed itself out and stalactites twinkled as shafts of light peeked in. For a moment, we even forgot we were floating in 40 F water in a body of rough water that has sunk its share of ships.

More information: All half day excursions for any and all TYF adventures start at $96 USD. Full days start at $158 USD; [www.tyf.com]

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