The COMMON SENSE (CS) project aims to develop cost-effective, multi-functional innovative sensors to perform reliable in-situ measurements in the marine environment. The COMMON SENSE sensors will focus on key parameters including eutrophication, heavy metals, marine litter (microplastics) and underwater noise. The project will focus on increasing the availability of sensor data and observations through the development and implementation of the Common Sensor Web Platform (CSWP), a software platform that will integrate the COMMON SENSE sensor data and observations and deliver them to the Web, in standard formats and through standard interfaces.