This thesis examines the impact of tourism on marine conservation in Koh Lipe, an island in southern Thailand. The objectives of this study were to (1) understand the social and environmental changes that occurred on Koh Lipe in recent decades and how these changes are impacting the marine environment; (2) investigate ongoing conservation efforts, and how local stakeholders are involved and envision a form of marine conservation responsive to their needs; (3) determine the values motivating and driving local-level engagement in marine conservation-related activities; and (4) explore the implications of the case study findings on conservation-development in Koh Lipe and reef-based tourism. The factors observed to contribute to marine degradation included overfishing, island infrastructure development and tourism activities. Community-based and co-managed conservation approaches have emerged to address these issues but local involvement is limited. Management implications aim for biodiversity conservation to be improved and linked to sustainable local livelihoods.