Will is 22 and based in Edinburgh, Scotland. At 17, Will became the youngest Brit to climb 9a at the time with Rainshadow at Malham Cove. Since then, Bosi has become one of the leading lights of GB Climbing. In 2018, he reached the final of IFSC Chamonix Lead Climbing competition which was the first time a male had reached a lead final since 1998. In 2020, Bosi became the first Brit to climb 9b abroad with his ascent of La Capella. If confirmed at 9b+, Bosi would be the first Brit to climb the grade with his ascent of King Capella, placing him in an elite club at the top tier of the sport.