San Isidro is a barrio in the island-municipality of Culebra, Puerto Rico. Its population in 2010 was 16.It consists of a part of the island of Culebra in the northeast, and of islands and islets such as Roca Speck, Cayo Norte, Cayo Sombrerito, Cayos Geniquí, Cayo Tiburón, and Cayo Ballena.