Ultimate Guide to the Full Distance Triathlon Wales in Pembrokeshire Compete in one of the most iconic triathlon events, set against the stunning backdrop of Pembrokeshire, Wales. Here's what to expect: Swim: Begin your journey with a thrilling two-loop, 2.4-mile (3.8 km) swim in the pristine waters of North Beach, Tenby. Energized crowds and the iconic "zig zag" stairs lead to a memorable transition. Average water temperature: 63°F (17°C). Bike: Tackle the scenic yet challenging two-loop, ...