How long does it take for a body to decompose at sea? What the hell happens to it? It's all about the temperature. Bodies tend to sink in colder water, and the skin absorbs water and peels away from the corpse within a week, slowly being eaten away by marine life. Bodies can stay recognizable for months. In tropical water, it’s a different story. Even a weighted body will normally float to the surface after three or four days, exposing it to sea birds and buffeting from the waves. Putrefaction and scavenging creatures will dismember the corpse in a week or two and the bones will sink to the seabed.