Sherpa's first successful climb was to Mount Cho Oyu at the age of 20. He went on to successfully summit dozens of mountains including Mount Everest, K2, Cho Oyu, Lhotse, Manaslu, Annapurna and Dhaulagiri, multiple times without supplementary oxygen. He is thought to have successfully summitted eight-thousanders a total of 18 times, almost all of them without oxygen.