El Astillero is a town and municipality located in the province and autonomous community of Cantabria in northern Spain. Situated at an elevation of 20 meters above sea level, the town lies at the foot of Peña Cabarga and is positioned approximately 7.5 kilometers from the provincial capital, Santander.
The geography of El Astillero is defined by the surrounding estuaries. It is bordered by the municipalities of Camargo, Villaescusa, Piélagos, Medio Cudeyo, and Marina de Cudeyo. The town is notably recognized for its shipyard and as a host site for the Spanish national Rowing Championships.