Ecotourism is being promoted as a sustainable alternative to mass tourism, although critics suggest that it may be just as damaging because it encourages increased use of natural areas. One of ecotourism's claimed benefits is the promotion of pro-environment attitudes and behaviours. However, this may not occur if ecotourists are already 'converted' to the pro-environment cause. To test this claim, a study was undertaken of ecotourists visiting Lamington National Park in southeast Queensland. A pre-/ post-visit questionnaire survey was conducted on-site, as well as a follow-up mail-out survey four months later. This paper presents results of that study in terms of four ecotourist groups. Results indicate that ecotourism can increase environmental knowledge and influence conservation views and behaviours. Of the four groups, coach day tour visitors were the least pro-environment initially but had relatively strong ecotourist motivations. They achieved the highest gains in knowledge and in the short term were influenced the most by the visit. In the long term, respondents who were the most pro-environment and who had learnt most during their visit were influenced the most. Therefore, for immediate effects of the experience on the uninitiated to endure, motivations need to be stimulated to encourage further involvement in and learning about nature. The question remains as to whether encouraging such involvement will have net benefits for the environment.