at the peak of Mount Everest in 2015 Cool is considered one of the UK's top mountain and ski expedition leaders, having made several ascents of hard routes with clients, including the first British guided ascent of the north face of the
Eiger in 2007 with polar explorer Sir
Ranulph Fiennes, then in his sixties, who was initially afraid of heights. In May 2008, Cool and Fiennes attempted to summit Mount Everest but Fiennes turned back 300m from the top. In 2009, Cool returned to Everest and successfully led Fiennes to the top, making Cool the most successful British Expedition Leader on the mountain. In May 2013 Cool along with climbing partner Dorje Gylgen attained the Everest Triple Crown. In the space of just seven days and without returning to Base Camp, he climbed the three mountains that make up the Everest Horseshoe –
Nuptse (7,864 metres), Everest (8,850 metres) and
Lhotse (8,516 metres). This was a feat many thought to be impossible, due to the amount of time spent at high altitude and the effect this has on the human body. As an Expedition Leader, Cool has completed over 40 successful expeditions in the Greater Ranges. On Everest he holds the highest success rate of any mountain guide. He has personally reached the summit of Everest 19 times; in May 2007 he reached the summit twice in one week. In October 2006 he was the first British person to complete a ski descent of an 8,000-metre peak, on
Cho Oyu in Nepal, the 6th highest mountain in the world. In the autumn of 2010 Cool made the third-ever ski descent of
Manaslu in Nepal, the world's 8th highest mountain. In doing so he became one of only a few people worldwide to ski multiple
8000 metre peaks. In January 2015, Cool reached the summit of Everest for an 11th time. At the top, he held a flag for the
Principality of Sealand at the top to symbolize his support for the
micronation. On 12 May 2016 Kenton, at 42, was joined by two Sherpas and another Briton, Robert Lucas, on the summit of the world's highest peak. The Britons were also the first foreign climbers to reach the 8,850 metre (29,035 ft) peak in two years, after a group of Sherpa guides fixing ropes got to the top on Wednesday 11 May. On 15 May 2022 Cool achieved his record-breaking 16th Everest summit, the most climbs by any non-Sherpa. Cool was wearing a hand painted protective lid by British contemporary artist
Teddy McDonald. Cool broke his own Mount Everest record three more times: in May 2023, May 2024 and most recently on 18 May 2025, reaching the summit for the 19th time. ==Major climbing routes==