Disclosed is a method and a device for improving the safety of a maritime platform, installed at sea or navigating at sea, including an observation of sea waves striking the maritime platform, an operation of the maritime platform being controlled via a control system. The method and device are suitable for: —acquiring elevation values of the surface of the sea at a plurality of points, making it possible to characterize at least one group of sea waves, a sea wave being likened to a wave defined by a period and an amplitude, —calculating at least one characteristic quantity of each group of waves, —comparing the calculated characteristic quantity to a hazard threshold, —if the comparison indicates the hazard threshold is crossed, raising an alert intended for the control system.