The San Martín tower dates back to the time of the Asturian monarchy, when King Alfonso III built this defense point against Norman maritime incursions. It is configured as a three-story, square-plan structure, topped by battlements, which could be raised on an earlier Roman foundation. This tower rises on a promontory at an altitude of 73 meters. Around it, various constructions were developed over time, highlighting a house with a gallery from the end of the 19th century.

The tower property is surrounded by a crenellated fence, which has a jetty in its eastern area.