This thesis investigates the use of Visionary Nature-Based Solutions (VS) within the H2020 VARCITIES project, focusing on the challenges of quantifying their benefits. It emphasizes the environmental, economic, and social advantages of VS, with particular attention to social impacts and stakeholder engagement. The Social Return on Investment (SROI) analysis was employed to measure these impacts, proving its potential for urban applications despite limited literature. Tested in Gżira, Malta, the methodology highlighted significant improvements in environmental quality, economic benefits, and social engagement. The study underscores the importance of stakeholder participation and provides insights into enhancing SROI to better capture social impacts in urban planning.