This study aims to uncover the key determinants of success for tourism start-ups, which has been gradually developing and expanding in the ecosystem of the domestic tourism industry. To this end, the four factors of the ERIS model, a proven model that has been used to derive the determinants of venture and start-up performance in various fields, were organized as a framework for research. Two rounds of Delphi analysis were conducted with academic, industrial, and policy-related experts. As a result, a total of 41 elements of success factors were derived: 13 from entrepreneur factor, seven from resource factor, nine from industry structure factor, and 12 from business strategy factor. In addition, it was confirmed that the 'understanding industrial trends' and 'business differentiation strategy' derived through the first Delphi open questionnaire appeared as the determinants for success reflecting the characteristics of the tourism industry. The AHP analysis also assessed that the entrepreneur factor among the four factors in ERIS model was the most important factor in determining the success of the tourism start-ups. It was found that the human capacity, especially entrepreneurs’ competence can be the key factor to the success in small companies such as tourism start-ups. Based on the results, theoretical and practical implications were proposed to foster and promote future tourism start-up businesses.