The Costa Rican coasts are at risk of local tsunamis. On both Pacific and Atlantic sides of Costa Rica there are coastal segments characterised by a flat relief, which increases the vulnerability of the coastal communities. In addition to tsunamis originating in the Middle American Trench (MAT), Costa Rican communities are at risk of a local tsunami generated by an earthquake in an undersea thrust fault system that runs along the Caribbean coasts of Costa Rica and Panama (NPDB). Furthermore, recent bathymetric studies reveal evidence of prehistorical submarine landslides in the Pacific Ocean capable of generating large tsunamis. The Golfo Dulce tsunami in 1854 in the Pacific and the Bocas del Toro tsunami in 1991 in the Caribbean are the real evidence of the hazard in the country. The University of Costa Rica is working on the implementation of the Tsunami Hazard Mitigation Program.