He took part as a climber in Chris Bonington's 1970 Annapurna and 1975 Everest Southwest Face expeditions (the latter as sirdar). Bonington said he consulted Pertemba frequently, sometimes to the irritation of the lead climbers when he accepted the sirdar's opinion over theirs of the capabilities of the Sherpas and even on the best route to be followed. He was expedition co-leader on the American first ascent of Gauri Sankar in 1979. He has climbed Mount Everest three times although he stopped climbing in 1995 while continuing to lead climbing and trekking expeditions.