For tourism development in areas where there are frequent problems with water shortage, it is important to assess water use potential from a geographic perspective. This study investigated the relationship between water use in the hotel sector and the amount of available water in Phuket for tourism carrying capacity assessment. Geographic information system (GIS) was applied to support spatial analysis. The studied hotels were in the size required to conduct an environmental impact assessment (EIA), totaling 178 hotels. There would be a total water use of 24,275 m3/day and 40,457 m3/day in the low and high seasons, respectively. In terms of annual water use, in the cases of lowest, normal, and highest possible consumption, there would be water consumption amounts of 8,860,021 m3/year, 11,303,606 m3/year, and 14,766,699 m3/year, respectively. From evaluating the capacity to support tourists in terms of water adequacy in Phuket Province, our results reveal that the amount of water in the province is insufficient to meet the needs of tourists. This is because the number of tourists coming to travel each year is ordinarily more than 10 million people, and there is a plan to accommodate 12 million tourists in 2023, but the amount of water that the province can procure is sufficient to support a maximum of not more than 8,986,600 tourists per year only if the water that EIA hotels store and produce themselves is included. This amount of water is still insufficient for the targeted number of tourists and other sectors, and the province’s water demand is likely to increase. In this regard, Phuket should hastily prepare a plan and measures to increase the amount of available water within the province.