Extreme geo-climatic events can occur everywhere in the world. The Great East Japan Earthquake, with a moment magnitude scale of 9.0 M on March 11, 2011, was one of these events and caused huge tsunamis that changed largely tidal communities on the Pacific coast of eastern Japan. However, subsequent long-term changes in the communities after such an extreme geo-climatic event have rarely been examined. Therefore, we performed the biological monitoring over a ten-year span, before and after the earthquake, that was supported by citizen volunteers. The results revealed that the most tidal communities returned to their original states in less than a decade, indicating that the nearshore communities were highly resilient to large physical disturbances like tsunamis if the surrounding environmental conditions were unchanged.