Lydia Bradey is a New Zealand mountaineer. She is best known for becoming the first woman to summit Mount Everest without supplemental oxygen in 1988.
Lydia Bradey was born to Royce and John Bradey in Christchurch, New Zealand. Her father was absent for most of her childhood, and she and her mother struggled financially. Bradey took up mountain climbing as a teenager; she went on her first wilderness expedition at the age of 14, and by 17 she had climbed to the summits of Mount Cook and Mount Aspiring. During this time she regularly climbed with her friend Rob Hall, and later met his business partner-to-be, Gary Ball. When she was 19, Bradey left New Zealand for a four-year international climbing trip, which included an attempt on Mount McKinley in Alaska and ten ascents of Yosemite's big walls, seven of which were the first ascents by a female.
Bradey became known in the climbing world in 1987, when she reached the summit of Gasherbrum II, thereby becoming the first Australasian woman to climb one of the world's fourteen 8,000 metre peaks. The climb proved controversial since Bradey was climbing on a permit for the adjacent Gasherbrum I (a peak she had abandoned in favour of Gasherbrum II due to bad weather), making her ascent illegal. In October 1988, Bradey successfully climbed Mount Everest, making her the first female to reach the summit without supplemental oxygen, as well as the first New Zealand female and the youngest New Zealander at the time. This ascent, like the previous year on Gasherbrum II, broke rules agreed with the Nepalese. Bradey had not had a permit for the route she climbed, and her teammates Rob Hall and Gary Ball said she had not reached the summit to avoid being banned from the mountain. When the Nepalese government threatened Bradey with a 10-year climbing ban, she too retracted her claim of a success ascent, only to reassert her claim to the summit later.
In 1994, Bradey graduated from the University of Auckland with a degree in physiotherapy. She completed a certificate of acupuncture in 1998 and became a certified climbing guide in 2000. Since then she has worked as an alpine guide based in Wanaka. Bradey made her second summit climb of Mount Everest in May 2008, twenty years after her first ascent. She climbed as a guide for a group of clients under the outfitter Wanaka Adventure Consultants (WAC). In 2013, Bradey made her third ascent of Everest, again as a WAC guide.
Bradey lives in Lake HÄwea, Otago with her partner Dean Staples.