This paper analyses the management status of Surin Marine National Park (Surin), the effectiveness of existing management strategies, their adaptation to the problems occurring and the results of the adaptations. Surin is situated at the upper part of Andaman Sea, Thailand. Its reputation as the best shallow-water reef in Thailand attracts more than twenty thousand visitors per year who enjoy diving on the eight square kilometres of reef. Visitor management arrangements include a visitor fee, boat permits, specific activities management, a zoning plan and an information centre. In common with many other national parks, Surin faces management issues relating to this use and the capacity to manage it to protect valued resources. The current five year zoning plan is rigid and inflexible and makes it difficult for management to respond to changing circumstances. These problems contribute to concern for the effectiveness of tourism management. In addition, survey of visitor attitudes towards, and knowledge about, management revealed that visitors lack recognition of current management approaches. To address these issues, some changes have been made to management arrangements. A mooring buoy system has been established to better identify use areas and manage the level of use of sites. However, in the absence of a recognized study of the associated impact factors and effect of this decision, this plan may not be entirely successful. While the biogeography of Surin is well known, little is known about the visitors, their expectations or activities. More effective tourism management will require such information and its use to develop strategies to match visitor needs with marine resource characteristics while protecting the resource. Further revision of management approaches is also recommended