The purpose of this study was to investigate the characteristics of the ability of mountaineers to identify risks using KYT photos of mountain routes, as well as the determining factors of that ability. Data were collected from 544 ordinary mountaineers and 30 experienced mountaineers, who tend to act as mountain leaders. They were shown photos of mountaineering routes and asked to identify risks for mountaineers based on the photos, in a period of five to ten minutes. Risks were identified by four other experienced mountaineers using the verbal protocol method. The results indicated that 1) although, in general, the mountaineers could identify risks in the photos according to the characteristics of the area depicted in the photos, some mountaineers showed a low ability to identify risks, 2) there were particular problems with identifying potential risks, and 3) while no difference in the ability to identify risks was found between groups with different amounts of mountaineering experience, the ability deteriorated with age. Experienced mountaineers identified the risks of mountaineering routes not only by perceptible cues in the photos, but also by inference of risk source details using an induced “schema of the mountain area,” and identified and evaluated risks in a manner similar to the recognition-primed decision model (Klein, 1998). The issues faced by mountaineers related to the ability to identify risks were discussed from the perspective of preventing mountain accidents.