This report is the final report for the research and technology) project "Underwater sensor system for close coastal and harbour control" conducted during the years 2010 to 2013. The project has worked on issues concerning local surveillance of harbour and base areas. The main focus has been on how to protect a ship or other object against an underwater attack. To a lesser extent close coastal surveillance with surface and underwater sensors in conjunction has been studied. At the beginning of the project the final delivery was defined to be a concept for an acoustic and electromagnetic tripwire for harbour and base protection. A prototype for a passive electromagnetic and acoustic tripwire (PEAT) capable of real-time automatic detection of a diver has been demonstrated in experiments in real harbour environments. PEAT consists of a passive acoustic tripwire (PAT) and an electrode tripwire (PET). Trials have been conducted in various locations in the world and the tripwires' performances have been evaluated using data from these trials. The automatic detection algorithms could be implemented in existing or future opertional systems with a relatively small effort. The project has participated in three international collaborations; the EDA project HAPS (Harbour and Base Protection Systems), SICCPA (Sensor Integration for Close Coastal and Port Awareness) with Canada and the EU project SUPPORT (Security Upgrade for Ports). The concept for an acoustic and electromagnetic tripwire for detection of divers in near real time developed within the project has been tested and further developed using data from those international cooperative projects. This report summarizes the achieved results and conclusions of the project.