Accurate information on ecotourism site suitability is crucial for effective planning, aiding in ecological conservation and local economic uplift. This study addresses the lack of documented ecotourism site suitability in the Lake Tana watershed of Ethiopia by evaluating factors such as elevation, slope, vegetation density, and proximity to water and infrastructure using Geographical Information System (GIS) and multi-criteria evaluation methods. The Analytical Hierarchy Process (AHP) combined with GIS was used to create a resource inventory and establish sustainable tourism criteria. A suitability map was developed based on weights from pair-wise comparisons of the selected criteria. Results show that 20% of the area, particularly near Lake Tana and water bodies, is highly suitable for ecotourism. Additionally, 50% is moderately suitable, 3.1% is marginally suitable, and 26% is unsuitable for development. These findings can guide resilient policies for ecotourism initiatives and help assess sustainable tourism in other regions. Regional tourism offices, Non-governmental Organizations, and policymakers can use this data to evaluate natural resource suitability for ecotourism, providing a foundation for further research in the field.