It is, claims the estate agent's blurb, one of the few island's off Belize's sparkling Caribbean coast with the "length and integrity" to support the take-off and landing of private jets.
But for DiCaprio, the Hollywood star and avowed environmentalist, his reported purchase of the £1.75m Caye is not just about owning his own private island. He is said to be attracted by the more basic pleasures Blackadore Caye has and wants to share them with like-minded eco-tourists by turning it into a luxury conservation resort.
There is no running water and no electricity. The few buildings collapsed after the last inhabitants moved out decades ago. What remains are white sand beaches, coconut groves and shards of Mayan pottery.
Just 25 minutes away by boat lies the world heritage site of the Belize Barrier Reef, identified by Charles Darwin, and among the world's richest marine ecosystems. Belize's mainland has spectacular forests. Its bird sanctuaries and reserves for howler and spider monkeys, a native jaguar and the critically endangered Morelet's croco-dile are renowned. Offshore there are manatee and some of the finest bonefish and tarpon fishing in the Caribbean. And should the natural attractions start to pall, a short eastward hop in the speedboat will bring the star and his entourage to Ambergris Caye with its luxury hotels, A-list holidaymakers and pulsating nightlife.
DiCaprio is joining an illustrious roll-call of private island-owners. Marlon Brando had one, James Cagney won one in a poker game, Mel Gibson has his and so does Johnny Depp. Before their split, Jennifer Lopez and Ben Affleck enjoyed their own celebrity love island.
But a friend of the Oscar-nominated actor said that he planned to turn the 104-acre island into a five-star resort for wealthy wildlife lovers. " He wants to make money without destroying the environment," the source said. "Energy sources will be renewable and it will be self-sustaining."
John Estephan brokered the deal with the Belize-registered property company Django Ltd. The buyer remains anonymous but many big US stars have been taking an increasing amount of interest in Belize.
Recent visitors have been the sportsmen Tiger Woods and Lennox Lewis and the actors Robert de Niro and Harrison Ford. They are lured there by the wildlife. Others enjoy the anonymity offered them by the local population, Mr Estephan said. "No one is going to come rushing down here because Leonardo DiCaprio has moved in. Even our prime minister walks down the street without a bodyguard. We say, 'We like you, we like what you do' ,and that's it."
DiCaprio is perhaps Hollywood's highest-profile environmental campaigner. He runs an eco-website alongside his fan site, blasting companies for environmental crimes and urging people to take sustainable holidays. He is a vocal critic of President George Bush's green record and spent much of last year travelling around the United States encouraging people to come out and vote.
The actor has won several awards for his environmental activism, and his foundation has funded green projects. His passion for the environment is said to date from 1999 when he made the film adaptation of Alex Garland's The Beach on Phi Phi in Thailand. Ironically, the film's producers were taken to court for allegedly removing foliage from the trees.
In an essay this year called Cities and Climate Change, he said he first became aware of environmental degradation growing up in the smog of Los Angeles in the 1970s.
He criticised the "sprawling growth of cities and our insatiable consumption" that was leading to booming demand for energy and increasing greenhouse-gas emissions. "Our actions may determine if we become a casualty in the war for a habitable planet for generations to come," he warned.
Splashing out: Who owns what
Plans to convert the lush Blackadore Caye in Belize into a self-sufficient eco-destination for the wealthy.
The Edward Scissorhands star spent £1.9m on Little Halls Pond Cay, a mile-long island in the Bahamas south of Nassau.
The Braveheart star paid £8m for the l5,400-acre island of Mago in Fiji. He is said to have bought it from a Japanese hotel company.
After his death, his beloved Tetiaroa in the south Pacific's Society Islands is being turned into an eco-destination.
JENNIFER LOPEZ AND BEN AFFLECK
The former golden couple bought the $10m, 83-acre Hampton island, off Georgia. They split last year.