Preventing coastal erosion and stimulating nature-based solutions on San Andres Technical cooperation to prevent coastal erosion on the island of San Andres, Colombia.As a result of the Delta cooperation between the governments of Colombia and the Netherlands, in 2017, the Coastal Erosion Master Plan for Colombia (PMEC) was developed. Erosion is a priority topic of the collaboration between the two countries. In this context, San Andres was identified as one of the most affected regions in Colombia, which led to the following project Technical cooperation to prevent coastal erosion on the island of San Andres. At the request of the territorial entity, the project aims to counteract coastal erosion on the island based on technical advice, including nature-based solutions and local knowledge. Although there are some areas where the effects of erosion are more noticeable, Governor Everth Hawkins selected Spratt Bight beach, as it is the most heavily used beach with the highest density of hotels on the island. Throughout the project, feasible areas for sand extraction to replenish the beaches were analyzed, taking into account possible socio-environmental impacts; previous studies; using a holistic vision that considers the Archipelago as an integrated unit; providing spaces for interaction between institutions and community representatives; and verifying possible solutions and technical information in the field. Furthermore, within this study, INVEMAR conducted technical field and laboratory work for a physical/chemical characterization of marine sediments and sands of the beach. The consortium developed the following possible solutions: 1. Close the breach ('the Channel') in the reef,2. Beach regeneration by dredging,3. Nearshore protection structures,4. Conservation and restoration of marine vegetation,5. Protective coastal vegetation.These solutions were presented to the communities and institutions, who expressed their concerns and expectations, such as possible interventions in the Seaflower Reserve, a highly vulnerable territory. Any intervention must be agreed upon by the authorities, the community, and other users. Artisanal fishermen, CORALINA (the Department's environmental authority), the Departmental Government, INVEMAR, the Ministry of the Environment, the National University, and the hotel industry discussed the feasibility of each proposed solution.Regenerating the beaches with sand extracted from the port’s access channel, the area to the west of Johny Cay, or the banks around the island is possible. However, the source of the dredged sediments must not affect the beaches' composition or aesthetic aspect. Closing the breach in the reef, with the assessment and license from the environmental authority, would help reduce the energy of storm surges entering Spratt Bight Bay through the channel to the west of Johny Cay. In addition, it would reduce the intensity of currents responsible for the dynamics of natural sand transport along the beach. Other suggested alternatives are implementing protective structures near the coast, conserving marine vegetation (seagrass meadows), restoring natural conditions, and expanding protective coastal vegetation. The proposed solutions should reinforce the natural coastal protection ecosystem, stimulate tourism, and support local livelihoods. The solutions cannot be considered as individual measures but as a set of solutions to be implemented where necessary and mutually reinforcing.Once the options have been analyzed, the departmental government will decide which solutions are most appropriate to mitigate coastal erosion and other negative effects of climate change in San Andres, particularly in Spratt Bight. The alternatives chosen by the government should be the subject of more detailed studies in a potential next stage, which could also be extended to other sectors of the island with severe coastal erosion conditions.