The Intergovernmental Coordination Group for the Tsunami and Other Coastal Hazards Warning System for the Caribbean and Adjacent Regions at its eighth session (ICG/CARIBE EWS-VIII, Port of Spain, Trinidad and Tobago, 29 April–1 May 2013), decided to conduct exercises named CARIBE WAVE on an annual basis leaving each Member State to define its level of participation. At its Twelfth Session in, Puntarenas, Costa Rica10-12 May 2017, the ICG/CARIBE-EWS, recommended that Exercise CARIBE WAVE 18 take place on 15 March 2018, with three hypothetical scenarios. The initial dummy messages for the three scenarios will be issued by the Pacific Tsunami Warning Center (PTWC), which is the CARIBE-EWS Tsunami Service Provider, on March 15, 2018 at 1400 UTC and will be disseminated over all its standard broadcast channels. 1) The first scenario simulates a tsunami generated by a magnitude Mw 8.6 earthquake located along the Southern Lesser Antilles. Event origin time: 14:00:00 UTC March 15, 2018. 2) The second scenario simulates a tsunami generated by a magnitude Mw 8.1 earthquake located along the Caribbean coast of Colombia. Event Origin time: 14:00:00 UTC March 15, 2018 3)The third scenario simulates a tsunami generated by a magnitude Mw 7.6 earthquake off the West coast of Puerto Rico. Event Origin time: 14:00:00 UTC March 15, 2018. The purpose of the exercise is to improve the Tsunami Warning System effectiveness along the coasts of the Caribbean and Adjacent Regions. The exercise provides an opportunity for the corresponding emergency management organizations to exercise their operational lines of communications, review their tsunami response procedures, and promote tsunami preparedness. Regular exercising of response plans is critical to maintain readiness for an emergency. This is particularly true for the Caribbean and Adjacent regions, where tsunamis are infrequent but can be of very high impact. All Emergency Management Organizations (EMO) are encouraged to participate and include the communities at risk. The initial dummy messages will be issued by the US Pacific Tsunami Warning Center (PTWC) on 15 March 2018 at 14:00:00 UTC (Universal Time Coordinated) for the three scenarios. These messages will be disseminated over all standard Tsunami Warning Centre broadcast channels. The dummy messages are issued to test communications with Tsunami Warning Focal Points (TWFPs) and National Tsunami Warning Centres (NTWC), and to start the exercise. As of 14:05 UTC the PTWC will only send by emails the simulated tsunami products to officially designated TWFPs and NTWCs according to the chosen scenario.