This study introduces a system based on continuous wave radarContinuous wave radar for the early detection of tsunamis. The system works considering that seawater strongly reflects electromagnetic waves, and it is composed of a digital signal synthesizer (DSS), a digital receiver, a circulator, and a prime focus parabolic reflector antenna, which acts as a transmitter and receiver by means of a circulator. A focused electromagnetic beam is generated employing the DSS connected with a prime focus parabolic reflector antenna. The electromagnetic wave is well concentrated, thanks to the parabolic radiators and the considered frequency band, and it travels parallel to the sea surface. When a tsunamiTsunami occurs, the sea level increases up to 50 m, as during the 2004 tsunami2004 tsunami, the electromagnetic beam intercepts the sea level front and is subjected to a strong reflection that can be easily detected at the receiver, providing information concerning the distance and the velocity, thanks to the Doppler effect, of the wave that is going to reach the seaside. The system is light and inexpensive and can be easily installed anywhere without infrastructure. The simulations demonstrate the potentialities of such systems as early detection alerts for tsunamisTsunamis.