A listing on the e-commerce site Mercado Libre offering Cerralvo Island — part of an expansive UNESCO World Heritage site off the coast of Baja California Sur (BCS) — for US $115 million has sparked controversy.
The listing from mid-April has drawn especially strong opposition from BCS Governor Víctor Manuel Castro Cosío, who has condemned the proposed sale, asserting the island is part of Mexico’s national heritage and vowing to block privatization efforts.
The 136.5-square-kilometer island, controversially renamed Jacques Cousteau Island in 2009, is being promoted by KW Metropolitan as a “sustainable development” project that could feature eco-hotels, renewable energy plants, an airport and conservation zones. KW Metropolitan is a brand of Texas-based Keller Williams, one of the world’s largest real estate franchises.
Satellite images and details in the listing confirm the property as Cerralvo Island, located 95 kilometers east of the city of La Paz in the Gulf of California — famously dubbed “the world’s aquarium” by the late explorer Cousteau because of its extraordinary marine biodiversity.

Castro Cosío clarified that the island — more than twice the size of Manhattan, New York — has been privately held by the powerful Ruffo family, whose legacy in Baja California and BCS dates back to the late 1800s.
But in recent comments in the regional newspaper El Sudcaliforniano, he stressed that “all islands, seas and lands should be considered national property” and urged federal authorities to review the island’s legal status. He also said any development would require environmental impact assessments from Mexico’s Environment Ministry (Semarnat).
Cerralvo Island’s ecological significance is undisputed: It shelters migratory species such as humpback whales, hammerhead sharks and endangered seabirds — and 20 years ago was designated a UNESCO World Heritage site alongside 243 other islands, islets and Gulf of California coastal areas.
Article 27 of Mexico’s Constitution restricts foreign ownership of coastal land and mandates federal oversight for island sales, though exceptions exist — such as Cayo Culebra, the last virgin island on the Riviera Maya, going on sale last year for a reported US $68 million. (No official announcements or media reports indicate the sale has been completed … in case you’re interested.)
KW Metropolitan’s listing — active as of Monday — faces skepticism from environmentalists who warn of irreversible harm to fragile ecosystems. While the listing touts “eco-tourism” and infrastructure, critics note the logistical challenges of building in pristine areas and the precedent such a sale would set.
The controversy echoes past disputes over Mexico’s islands, such as San José Island, also in the Gulf of California. It is privately owned and undeveloped with no permanent residents.
Cerralvo Island is also undeveloped as well as uninhabited, with no large-scale infrastructure. It is named for the 3rd Marquis of Cerralvo, Don Rodrigo Pacheco y Osorio, who served in the early 1600s as viceroy of New Spain (which would become Mexico).
Known for its rugged natural beauty and extraordinary marine biodiversity, the island currently serves as a destination for adventure tourism and traditional fishing.
With reports from El Sudcaliforniano, BCS Noticias and Infobae