The Marine Corrosion Test Site (MCTS) "El Bocal" has been commissioned by CTC and is now ready for mounting of samples coated with the biofouling and corrosion resistant materials under development in the ACORN project. This new installation is located at the shoreline of the Cantabrian Sea coast, a few kilometres away from Santander city and with an easy access for installation and monitoring activities. In this structure, three different corrosive environments are present: splash, tidal and submerged. The framework of galvanised steel is anchored to a concrete vertical wall and provides a support for the specimens to be tested. The location selected is a first class place for testing new coatings and components under real marine exposure.