The five scenarios describe plausible changes in 15 external drivers of the socioecosystem of the Mar Menor and surrounding Campo de Cartagena between 1964 and 2070. These scenarios were developed for evaluation of their impacts on Key Performance Indicators of sustainability using a simulation model based on System Dynamics. This model, developed by Martínez-López et al (2022) can be consulted here. Historic data combined with the Shared Socioeconomic Pathways (SSPs) from the IPCC report ‘Global warming of 1.5°C’ and the Representative Concentration Pathways (RCPs), were used as starting point to develop the model-specific scenarios. The five scenarios are based on SSP 1, SSP2, SSP4 and SSP5 in combination with emission scenarios that will keep global temperature rise below 1.5ºC. The BAU scenario represents a combination of SSP2 without any climate change. The detailed documentation of SSPs from O’Neil et al (http://dx.doi.org/10.1016/j.gloenvcha.2015.01.004) and subsequent expert interviews and input received during stakeholder workshops organised in the framework of the COASTAL project were used to prepare the region-specific time-series of the 15 variables for the Mar Menor and surrounding Campo de Cartagena. The 15 external drivers are: Agricultural revenue per hectare Growth rate of agriculture Percentage of nutrients that are metabolized by the native lagoon ecosystem Average excess of fertilizer use Yearly effectiveness in nutrients reduction of nutrients, soil and water retention measures Electricity Price Mean number of hours per day of photovoltaic electricity production Photovoltaic energy facilities growth rate in Megawatts installed Growth rate of tourism Average percentage of groundwater desalinated Agricultural water demand per hectare Catchment water sources Urban wastewater treatment plant effluents Yearly average of sea water desalination Amount of water transferred from the Tagus river (RCP15ATS)