The purpose of this study is first to propose a comprehensive evaluation model for sustainable island tourism, and then to provide guidelines and suggestions for the development thereof. Based on the advantages of using fuzzy set theory, this study’s method included the fuzzy Delphi method (FDM), the decision-making trial and evaluation laboratory (DEMATEL), the analytic network process (ANP), and FDM- DEMATEL-ANP (FDANP). From the literature review results and experts’ surveys, the dimensions of the evaluation criteria for sustainable island tourism are governance, economy and finance, socio-culture, and the environment. Compared with other studies, its major contributions and differences are the governance and finance dimensions, and the evaluation criteria for the marine industry, marine cultures, and marine environments. The findings show that the relative importance of the dimensions from high to low are economy and finance, governance, the environment, and socio-culture. The top five key criteria begin with having an official administration organization, having a tourism industry, and revenue uncertainties based on public health events. These, along with policies and regulations, and local food and drink, are thought to provide the necessary conditions for sustainable island tourism. The implications for theory and practice and future research directions are discussed.