The objectives of this paper are to clarify how valuable natural resources associated with tourism industry are; to assess efficiency of the relation between water resources and sustainable development of tourism industry; to promote ecofriendly skills of visitors in order to have an interactive relationship with tourism assets; to maximize economic, social and environmental benefits for both local communities and tourists; to find out the value of Iran’s experience with tourism development with conservation of natural resources for other countries, in particular for Ukraine. Methodology. The research used statistical methods (based on the goals declared in the 20YPPT & SDP plans, Iranian population forecasts, the number of international and domestic tourists in the country is determined before 2025, the amount of water needed for the tourism sector is calculated according to statistics, the amount of available water per capita is calculated and its rate of decline is specified, the volume of water for the domestic sector and necessary for tourists is determined), the study of documents and interviews with experts within Delphi regarding the method of systematic sampling. Results. The authors calculated the predicted values of the influx of foreign and domestic tourists for the period of 2016-2025 based on goals declared in 20YPPT & SDP plans, Iranian population forecasts. Therefore, 7.8 million foreign and 51 million domestic tourists were expected in 2016, and 27.95 million and 53.5 million, respectively in 2025. The volumes of water consumption in the tourism sector are predicted in three scenarios: water use is stable and the same with local residents; water use is twice as much as that of local residents; water use is in parallel with global demand growth rates of 4-8% per year. According to the first scenario, the share of the tourism sector in water use will increase from 6.15% to 19.5%, according to the second one – from 19.1 to 69% and according to the third one – from 7.1% to 37.1%. The first scenario is defined as optimal, the second one is identified as crisis, and the third is considered. The average amount of water required for the tourism sector, taking into account unaccounted water (from 0.53 billion cubic meters in 2016 to 1.24 billion cubic meters in 2025) was also determined. Scientific novelty. In the study, based on 20YPIT and SDP plans, the volume of tourist flows in Iran was predicted, the volume of water consumption in the tourism sector in Iran was predicted in three scenarios, and a conceptual model of the consequences of unplanned water management in Iran’s tourism for 2016-2025 was developed. Practical significance. This study explains the nature of the impact of the tourism sector on water resources until 2025, determines the exact amount of water that tourists may need in these years, which makes it possible to make effective decisions by identifying weaknesses and opportunities.