Following the COVID-19 pandemic, the tourism sector has emerged as one of the most resilient industries. In 2024, many countries are experiencing a strong recovery, with tourism flows returning to pre- design interpretation and guiding sustainable development strategies at the territorial scale. This paper applies the STESY model in the Istrian region of Croatia—an area offering a rich blend of cultural, historical, and natural assets. The study aims to construct a strategic framework for local tourism system development, grounded in a robust analytical process that includes open data and cluster analysis. Findings reveal a strong seasonal concentration of tourism in the summer months, posing significant challenges to economic stability in the off-season. Developed in collaboration with architecture students at the University of Basilicata, the proposed strategy—“CROATIA 365”—seeks to enhance the regional tourism ecosystem through year-round planning initiatives. The paper outlines the methodological approach, presents the case study analysis, and concludes with key insights, limitations, and recommendations for future policy and planning interventions aligned with the New Urban Agenda. Pandemic levels of 2019. This trend confirms the strategic role of tourism in driving socio-economic recovery and in shaping new models of sustainable territorial development. Tourism is analyzed using an integrated approach that combines open data and quantitative analysis.