The sources of marine debris (MD) on a small island are largely dependent on the activities on and around the island, one of which is tourism. In this study, the magnitude and tourists’ perceptions of MD on a small tourism island (Tidung Islands, Jakarta, Indonesia) were assessed. The results indicated that the tourism is one of the largest waste-generating sources. Plastic waste formed the major proportion of the solid waste, accounting for 83.86% of the total. The unmanaged tourism waste led to a clean-coastal index corresponding to the category “extremely dirty” and decreasing visitors’ acceptance index. The resulting conditions will make the tourism unsustainable. In tourism, waste management should be focused on, including prevention and collaborative actions with residents and tourism actors. In addition, the tourist awareness campaigns must be conducted prior to tourist-visitation on the island.