Urban green infrastructure (GI) aims to increase resilience to climate change and provide ecosystem services, bringing benefits to the mental and physical health of residents and visitors. However, in most cities today, GI is fragmented and does not meet the needs of a growing population. The objective of this research is to evaluate the GI of Lagos in southern Portugal and, according to the results obtained, design solutions that help to increase the urban resilience projected for the population of 2051. The GI of Lagos is projected to increase from 27 m² of green area per inhabitant in 2021 to 44 m² in 2051, in line with the recorded population increase of 7%. Accessibility to GI was estimated based on the 3/30/300 rule, using a 30-meter strip for existing trees and a 300-meter strip for parks. The accessibility area, totaling 467 ha, corresponds to 58% of the residential area. Based on the GI analysis, an urban green corridor was designed to connect existing and planned green spaces, with the aim of counteracting the current landscape's fragmentation and increasing the city’s resilience, providing multiple benefits for both the environment and the city’s inhabitants. A comparative analysis with successful case studies such as that in the Emerald Necklace in Boston, the Vitoria-Gasteiz Green Belt in Spain, and the Monsanto Green Corridor in Lisbon, Portugal, was conducted to inform the projected GI.