This research paper offers a thorough evaluation of Lahore’s sustainable surface water, considering climate change and transboundary diversions. Addressing these challenges necessitates a shift from groundwater to surface water sources. The first step involves calculating gross water availability for Lahore. Additionally, assessing future climate change impacts and transboundary interventions on surface water flows is crucial to ensuring sustainable water availability. The findings reveal severe stress on Lahore’s water resources due to rising demand, reduced availability from factors like over-extraction and climate change, and significant transboundary diversions from the Indus River System. Meanwhile, the demand for water keeps increasing. There are substantial variations in water availability throughout the year, with higher rainwater availability during the monsoon and reliance on link canals and river water during the non-monsoon season for urban water needs. To address these challenges, the study suggests diversifying urban water supply sources by diverting water from the Chenab River through link canals in non-monsoon months. This approach enhances water availability and groundwater replenishment. The research provides a comprehensive analysis of Lahore’s water resources, incorporating technical tools to assess climate change and transboundary diversions’ impact. The proposed management plan offers practical solutions for water scarcity and serves as a valuable resource for policymakers, researchers, and practitioners in water resource management. The study’s implications extend to regions facing similar challenges, emphasizing the importance of a holistic, integrated approach to water resource management that considers transboundary issues and climate change.