Icacos Cay (Spanish: Cayo Icacos) is the largest uninhabited cay forming part of a small chain of cays, reefs, and islets located off the coast of the barrio of Cabezas in the municipality of Fajardo in northeastern Puerto Rico. Along with Palominos island, it is part of the La Cordillera Reef Nature Reserve and under the jurisdiction of the Department of Natural Resources and Environment. Icacos is a fifteen-minute water taxi ride from Fajardo. The cay is a popular snorkeling and beach tourism destination.

For some time, there was a limestone quarry on the southern part of the island, with a short railroad system to shuttle limestone from the quarry to the pier.

• List of islands of Puerto Rico

• *Biobay Fajardo Archived 2017-03-07 at the Wayback Machine