Isla Cardona, also known as Sor Isolina Ferré Island,[1] is a small, uninhabited island located 1.30 nautical miles south of the mainland Puerto Rican shore across from Barrio Playa,[2] on the west side of the entrance to the harbor of Ponce, Puerto Rico.

[4][5] The island gained notoriety in 2010 when the Puerto Rican Bird Society made it a target for the eradication of the black rat.

The short distance from the mainland shore makes Cardona a popular landing point for aquatic events such as kayaking and summing, and every year the island is visited by dozens of swimmers in the annual Cruce a Nado, an international swimming competition sponsored by the Ponce Municipal Government.

"[13] The ferry trips ceased in January 2020 after a major earthquake struck the area, but restarted six months later.

In 2010, the Sociedad Ornitológica Puertorriqueña (Puerto Rican Bird Society) and the Ponce Yacht and Fishing Club launched a campaign to eradicate the black rat from the island.