Yes, the KIP works at sea, on the nearby coastline, up to more than 5 km! To visualise in detail the coverage of the KIP on this area, look at our coverage model here. The simulations take into account a KIP placed 1 meter above sea level. To ensure the dispersion of the radio waves of the KIP, and to counter the effects of the waves, we advise you to wear the KIP on your chest for example.