This paper examines tourist perceptions of sustainability in Manuel Antonio/Quepos, Costa Rica and Texel, The Netherlands. It also reviews tourist opinions of site-specific sustainability aspects and assesses differences between tourist types and their perceptions of sustainability. The ecological dimension of sustainability was perceived the most important, followed by social-cultural and economic dimensions. Among tourists to Manuel Antonio/Quepos there was no distinctive difference between the last two dimensions while the economic dimension was far less important among Texel tourists. Loss of local lifestyles and processes of urbanisation were the most serious problems perceived in Manuel Antonio/Quepos. For Texel, a fewrespondents indicated problems such as increase of prices, urbanisation and loss of local lifestyles. Results demonstrate tourist awareness of sustainability issues and that in the long run this awareness might lead to changes in tourist preferences.