Natural resources such as crystal clear water, white sandy beaches, untouched corals, interesting landforms and landmarks, and variety marine life form the main factors that attract tourists to fly across the globe, seeking for the purest nature can offer. The congregation of tourists into natural destinations have resulted demand for more tourist infrastructure such as resorts, jetties and other basic facilities to cater the growing needs of the incoming tourists. Small and fragile island, such Mabul Island, located some 30 kilometers the town of Semporna, Sabah, Malaysia, is one of the many islands in the South-east Asia that are experiencing intense growth in both physical tourist development as well as tourist activities. The development and activities have resulted in some undesired impacts on the socioeconomic as well as on the natural environment of her ecosystem. This paper reports on a study that evaluates the state of the physical environment of selected sites in Mabul Island focusing on their physical carrying capacity of each site. While the ultimate aim of this study is to propose the eventual numbers that can serve as the guiding principle of the sites, it also realizes that physical carrying capacity is very much influenced by the level of physical development as well as tourist activities.