Thermal tourism expenditures have an important role in the development of thermal tourism and achieving a sustainable competitive environment. The main purpose of this study is to examine the thermal tourism efficiency levels of the top 20 countries that provide thermal tourism services and to offer solutions for increasing efficiency for countries that have problems with efficiency. In the study, the first 20 countries serving within the scope of Thermal Tourism were sampled and a purposeful sampling method was used. The efficiency of these thermal tourism expenditures was evaluated with Data Envelopment Analysis (DEA) with the help of seveninputs and one output variable. VZA's input-oriented CCR (Charnes, Cooper and Rhodes-Fixed Scale Based on Scale) and BCC (Banker, Charnes and Cooper Variable Return by Scale) models were used. It was determined that half of the countries according to BCC model and 10% of the countries according to CCR model operated effectively. It should continue to improve its thermal facilities and country facilities in order to maintain its presence in the top 20 rankings of countries that are efficient in these areas and to achieve sustainable competitive advantage.