Climate change is having a major impact on high mountain areas, with glacier retreat and permafrost warming. Alpinism is deeply affected by this changing environment, which increases the technicality of the routes, their dangers, and the uncertainty of the periods of suitable climbing conditions during the summer. This raises the question of how recreational alpinists perceive and adapt to changing conditions. To answer this question, this paper reports the results of a quantitative social media survey of European alpinists based on the substitutability theory. The results from the 1071 completed questionnaires show that climate change and its impacts are clearly observed and identified by recreational alpinists; the higher the awareness of the changes, the more likely they are to engage in adaptation behaviours such as temporal, activity and spatial substitution, and informational coping. Furthermore, the more respondents perceive that climate change is affecting their practice in terms of degraded routes, increased risk, or increased frequency and magnitude of rockfalls, the more they engage in adaptation behaviours. Although adaptation seems to be sufficient to ensure satisfactory practice conditions, the development of communication for less informed alpinists, as well as the development of climate services, could be valuable to ensure sustainable and safe practices.