In early 1932 Penderel joined an expedition led by Count László Almásy to locate the legendary lost oasis of Zerzura in the plateau of Gilf Kebir, which lies in the southwest corner of Egypt, and southeast Libya. Reconnaissance flights over the area located a two large wadis green with vegetation, but before they could find a way to reach them overland the expedition ran out of supplies and had to return to Cairo. In March 1933 Almásy mounted another expedition in which Penderel took part, by which time Patrick Clayton of the Desert Survey had discovered the entrance to Wadi Abd el Malik, and explored the Kufra Oasis. They mapped the southern and eastern sides of the Gilf Kebir and on western side discovered Wadi Talh. They then visited Jebel Uweinat, south of the Gilf Kebir, where Almásy discovered prehistoric rock paintings. On 8 January 1934, Penderel gave a lecture on his expeditions to the Royal Geographical Society, who admitted him as a Fellow.