The Cabo Blanco Absolute Natural Reserve is a Nature Reserve of Costa Rica, part of the Tempisque Conservation Area in the province of Puntarenas, covering an area of 3,140 acres (12.7 km2) terrestrial and 4,420 acres (17.9 km2) marine on the southern tip of the Nicoya Peninsula near Malpais.

The site is home to the San Miguel Biological Station which was developed to promote and support teaching, research, and environmental education and has facilities that include classrooms, laboratories, and a reference library.

The reserve was created in 1963 due to a campaign started by Olof Weisberg and was the first major conservation project in the country