Sea mines are a military defense tool used to protect certain waters from enemy ships or attacks from under the sea. Sea mines are usually planted on the seabed or floating on the surface of the water.

Sea mines can be of various types, but generally they are equipped with explosive mechanisms that are activated by contact with an enemy ship, acoustic waves, ship magnetism, or water pressure. Once sea mines are activated, they explode and cause major damage to nearby ships or marine structures.

Sea mines are one of several maritime defense tools used by navies around the world. They are an important part of the defense strategy to protect water areas, ports and shipping routes from the threat of attacks by enemy ships. Sea mines can also be used offensively to hinder the movement of enemy ships and protect certain areas from maritime attacks.