This paper assesses the use the Global Sustainable Tourism Criteria (GSTC) indicators for monitoring tourism along a mountainous route. The study was carried out along a mountain route in the Drakensberg Mountains of South Africa. A survey was carried out among tourism businesses, local communities and local government officials located along the Maluti Route, which passes though the eastern part of the Free State Province of South Africa. This study constitutes the first assessment in which the GSTC indicators are applied in the assessment of the sustainability of route tourism in South Africa. The study first evaluated the importance of each indicator by considering the level of application in tourism business organisations before examining the perceptions of local community members and local government officials regarding the applicability of the indicators in the assessment of tourism sustainability. The results suggest that there is a general appreciation of tourism sustainability among tourism business operators although shortcomings were evident on environmental and socio-economic indicators. In conclusion, the paper suggests ways through which tourism sustainability could be enhanced among different players along the Maluti Route.