Some 1,500 extreme fitness competitors flocked to Wimbleball Lake on Exmoor National Park to compete in the Ironman 70.3 competition.
Challengers faced a gruelling 1.2-mile (1.9km) swim, an 56-mile (90km) bike ride, and a 13.1-mile (21km) run - 70.3 miles in total.
The top 100 will compete in the Ironman World Championship in Clearwater, Florida, next November.
Winner Fraser Cartmell, from Stirling, finished the race in 4h 17m.
He said: "It all adds up to such a demanding event.
"It's a fantastic thing to get through."