The Great East Japan Earthquake and Tsunami on March 11 in 2011, caused immense damage to marine ecosystems and marine products (fisheries and mariculture), both nearshore and offshore, on the Pacific coast of northeastern Japan (the Tohoku region). The rebuilding of towns and recovery of fisheries is proceeding only slowly because of the extensive devastation. Therefore, helping the restoration of marine ecosystems and revitalizing the fisheries and marine-product industries in these coastal areas have become pressing issues. In order to accomplish these urgent tasks, as well as to learn how to cope with such disasters in the future, scientific investigation is essential to understand the effects of such strong disturbances on marine ecosystems and to monitor the process of their recovery. However, such large-scale investigation is impossible by an individual or an independent research institution. Accordingly, the TEAMS (Tohoku Ecosystem-Associated Marine Sciences) project was created as a project at the national level. This paper introduces the overview of the TEAMS project.