A notorious prison island turned natural paradise

 

In 2019, Mexico shut down its infamous Islas Marías prison—the last remaining island penal colony in the Americas. Today, the former prison archipelago has been reborn as a protected biosphere reserve, welcoming tourists on carefully managed, navy-led excursions.

At the ferry terminal in San Blas, a coastal town in western Mexico’s Nayarit state, I stood in line behind two men in military fatigues carrying rifles. Moments later, a guard walked by with a sniffer dog that thoroughly inspected my backpack. Alongside a few hundred middle-aged Mexican tourists, I was about to board a navy-organised weekend tour to María Madre, the largest of the four Islas Marías islands—once ominously nicknamed “Mexico’s Alcatraz.”

Unbeknownst to me, my visit came just before U.S. President Donald Trump ordered the reopening and expansion of Alcatraz—the former island prison near San Francisco that closed in 1963 and has since become a major tourist attraction. Like Alcatraz, the Islas Marías now allow visitors to walk through the old prison cells. But while the American site is largely a monument to its own dark past, the Mexican island is also a model of environmental restoration.

Roughly 130 kilometers off the mainland, María Madre covers about 145 square kilometers and belongs to a four-island reserve overseen by Mexico’s navy. Since 2022, tourists have been permitted to visit the island on four-hour ferry trips from San Blas or the city of Mazatlán. Tours are strictly regulated and limited to designated areas.

For many Mexicans, the Islas Marías are legendary. The prison, founded in 1905, once housed some of the country’s most dangerous criminals and was immortalized in Mexican director Emilio Fernández’s 1951 film Las Islas Marías.

“They used to keep the really big criminals here,” said fellow passenger Francisco Espinosa, who explained that he was inspired to take the tour after watching the film that showcased the island’s beaches and the salt flats once worked by inmates. “It’s like Alcatraz—everyone knew about this prison.”

The island is known for its strong winds and the presence of an active military base, so before setting off, we were required to watch a safety video outlining emergency procedures—including what to do in case of a tsunami or a gas attack (for the latter: cover your nose and run). As the ferry continued its approach, I caught sight of giant sea turtles surfacing in the waves—an unexpected glimpse of the wild beauty surrounding us.

That natural wonder only grew once we stepped off the concrete jetty on María Madre and dropped our bags at the visitor accommodation complex. Herds of wild goats scattered from walkways that wound between buffet halls and souvenir shops, startled by the sudden influx of tourists. Their hooves clattered on the pavement, mixing with the sounds of a cascading man-made waterfall and the sharp, echoing squawks of birds in the trees above.

One of our guides explained that the raucous cries came from the green Tres Marías amazon parrots, a species found only on the island and now in the midst of mating season. In the prison era, inmates would sometimes have family members smuggle the birds off the island to sell. Boas once also suffered a similar fate—captured and skinned to make snakeskin belts.

My assigned lodging was a breezy, whitewashed villa that guides told us had once housed inmates. In fact, some prisoners were allowed to live with their families on the island and moved with relative freedom. But not all had it so easy. Many were forced to work under punishing heat on the salt flats or in shrimp farms. In 2022, a former inmate told the Los Angeles Times that she remembered 500 women sharing just five bathrooms. “We lived in a chicken coop,” she said.

In 2010, while the prison was still in operation, UNESCO designated the Islas Marías as a biosphere reserve, recognizing the region’s rich biodiversity across its dry forests, mangroves, scrublands, reefs, coastlines, and open ocean. In addition to the smuggled parrots of the past, the islands are home to 18 other endemic species, including unique raccoons and rabbits. Mexico’s National Commission of Natural Protected Areas (CONANP) is now responsible for safeguarding the fragile ecosystem, which evolved in isolation for over eight million years. Meanwhile, navy-run tours lead visitors through the remnants of the prison and educate them about the islands’ unique flora and fauna.

“This is tourism for exploration, to connect with nature,” said then-President Andrés Manuel López Obrador in 2022. “What was once a hell is becoming a paradise.”

Plan Your Trip

When to go: All-inclusive tours to the Islas Marías run year-round from San Blas or Mazatlán in Nayarit state. Ferries depart on Fridays and return on Sundays.

How to book: Visit visitaislasmarias.com to book a tour package, which includes accommodation, guided excursions, ferry transport, and meals. Prices start at around 10,000 pesos (approximately £390) for a solo traveller.

What to bring: There are no ATMs on the islands, so bring cash for extras like snacks, alcohol, souvenirs, optional bicycle rentals, and tips. A hat, sunscreen, and anti-nausea medication for the four-hour ferry ride are also recommended.

Still, it’s the prison’s dark past that draws most visitors. On a group hike, our guide pointed out a rusted metal box perched near a cliff. It resembled a sentry post, but was in fact a punishment cabinet once used to discipline inmates—positioned to trap the searing heat of the morning sun. Tourists took turns stepping inside and pulling its creaky door closed, grimacing at the claustrophobic heat.

After a buffet lunch accompanied by smooth saxophone covers of Elton John songs, we boarded a bus that rumbled down dusty roads toward the former maximum-security wing. As we neared the imposing grey complex—surrounded by fences crowned with barbed wire—“Macarena” blared from the bus speakers, a jarring contrast to the desolate scenery.

Following Mexico’s 2006 declaration of war on drug cartels, the prison evolved from a relatively open facility to a conventional high-security institution. In 2011, a new maximum-security section was opened, modeled on U.S. prison design: stainless steel furniture, clanging doors, and compact cells with metal bunk beds. Tourists leaned between cell bars to snap photos. Our guide recounted how a 2013 riot over food rations led to the section’s closure soon afterward. Today, the only movement between the abandoned watchtowers comes from roaming wild goats.

Before becoming a high-security prison, Islas Marías served as a place of exile for petty criminals and so-called "undesirables." In 1910, President Álvaro Obregón began sending political opponents to the islands, and in the 1920s, it became a holding site for Catholic supporters arrested during the Cristero War (1926–29).

One of the island’s most prominent political prisoners was writer and activist José Revueltas, who was sent there twice in the 1930s. A member of the banned Mexican Communist Party, he was convicted after participating in a union strike. A mural of the bespectacled, long-bearded Revueltas can be found on the wall of the hotel check-in building.

Later, the bus took us to a sun-drenched graveyard, where we stopped by a white cross marking the grave of José Ortiz Muñoz, known as "El Sapo" (The Toad). Muñoz, an alleged former government hitman accused of murdering hundreds of people, was sent to the island in the 1960s. He was eventually killed by fellow prisoners with machetes. Our guide pulled out her phone and played El Sapo, a lively song by singer Chalino Sánchez, as an iguana darted across the nearby tomb, its tail disappearing beneath the tiles.

Reports from former residents of Islas Marías suggest that even less-known killings occurred there. In 2004, island chaplain Francisco Ornelas wrote, "It is rumoured – and rumours thrive here – that people who were disappeared are buried on the other three islands, now deserted except for the visits of illegal fishermen and drug traffickers."

Access to the waters surrounding Islas Marías was restricted after María Madre became a penal colony in 1905. Fishing was further limited in 2000 when the area was designated as a biosphere reserve by Mexican authorities, ahead of its official declaration by UNESCO in 2010. In 2021, fishing restrictions were tightened once again, with all commercial fishing without a navy-issued permit banned in the region.

Despite these measures, conservationists argue that illegal fishing continues to thrive without effective enforcement. Octavio Aburto-Oropeza, a marine conservationist and professor at Scripps Institution of Oceanography, shared this concern when I spoke with him after the tour. "I know companies that not only offer recreational fishing around Islas Marías, but also spear fishing," he said.

Having dived the waters around Islas Marías on two separate occasions, Aburto-Oropeza noted that while illegal fishing is a persistent issue, the reefs and marine ecosystem remain relatively healthy, thanks to the archipelago's isolation and the limited number of visitors. He believes that both the navy and the National Commission of Natural Protected Areas (CONANP) should step up efforts to combat illegal fishing and establish clear goals for the restoration of reefs and marine species. He also sees potential for responsible tourism to support these conservation efforts. "Touristic activities, especially diving, could help enforce conservation projects," he explained, envisioning a tourism model that balances exploration with preservation.

I hope to return someday, perhaps to dive or explore more of the island’s historical sites. A guide showed me photos of rooms currently off-limits, including decaying chambers filled with quirky octopus sculptures created by former prisoners. She mentioned that, with time, these buildings might be safe to visit.

On the ferry ride back to San Blas, I chatted with fellow passengers about parrots, torture boxes, and the surreal experience of stepping into "Mexico’s Alcatraz." Not a single one of them expressed a desire for the prison to reopen.