A private island is a disconnected body of land wholly owned by a single private citizen or corporation. Although this exclusivity gives the owner substantial control over the property, private islands remain under the jurisdiction of national and sometimes local governments.
Compared to property on the mainland, an island property has much more restricted access, both by potential trespassers and by the residents, who need to transport all supplies by boat or aircraft. Livestock has often been kept on islands, because an island is a natural enclosure, preventing the escape of cattle and sheep.
There are many thousands of uninhabited islands in the world with potential for commercial development of tourist resorts or private recreational use. Commercial development of uninhabited islands can raise ecological concerns, as many have a fragile environment. Some islands can be bought undeveloped, while others already have roads and/or houses. Islands are also available for rent. Some celebrities have their own private islands.
There are widely varying government policies regarding private islands: for instance, islands off the coast of China, like any other land within the country, cannot be purchased outright, but only leased from the government for a maximum period of 50 years. Virtually all islands in the world are claimed and governed by some national government. That nation's laws apply, and any attempt by the owner to claim sovereignty would generally be unrealistic. Nevertheless, some people still try to set up their own micronations on islands, like real-estate millionaire Michael Oliver's attempt at building a libertarian city-state called the Republic of Minerva in the southern Pacific Ocean.
"Private" islands in the United Kingdom, Brazil, Chile and other countries are not legally entirely private – any foreshore, such as a beach, is owned by the state, and is hence publicly accessible property, despite what the owners of the land on the island may wish to claim. The same applies to freedom to roam in Nordic countries: only the yard of a house and the immediate vicinity is legally protected against trespassing, and the water bodies around the island are freely navigable.
Since 1992 a number of cruise lines have acquired “private islands” to offer their customers exclusive beach experiences. Such islands (or sections thereof) were further developed to have restaurants and perhaps additional attractions such as parasailing, waterparks, zip lines, horseback riding, spas and more. Some islands have piers, others are reached by tender. The purchase of an island allows the cruise line to achieve greater control over the venue and to influence the quality of experience of their passengers. Certain private islands may be used not only by the cruise line that bought the property but also by associated lines.
List of "private islands" of cruise lines
- Castaway Island, owner Disney Cruise Line, pier access
- Labadee, Haiti, a peninsula, owner Royal Caribbean Cruises, pier access
- Great Stirrup Cay, Bahamas, owner Norwegian Cruise Line
- Little Stirrup Cay (Co Co Cay), Bahamas, owner Royal Caribbean Cruises
- Harvest Caye, Belize, owner Norwegian Cruise Line
- Half Moon Cay, Bahamas, owner Holland America Line
- Princess Cays, part of Eleuthera, Bahamas, owner Princess Cruises, bought in 1992
- Ocean Cay Marine Reserve, Bahamas, MSC Cruises, (under construction, 2016)
- Sir Bani Yas Island 'Beach Oasis' at Sir Bani Yas, Abu Dhabi, MSC Cruises
The real estate market for private islands varies globally. Prices tend to be lower in Nova Scotia, parts of Michigan and Maine, and parts of Central America; and higher in Europe, the Bahamas, and Oceanic countries like French Polynesia. Islands with amenities have higher market value and are not sold as frequently. Some are available for travelers to rent, a trend which increased in the 2000s with economic recession making it more difficult for some owners to maintain them.
In the 2000s, the United States housing bubble increased the cost-per-acre for private islands. The effect was fueled by the advent of the Internet, which provided greater access to island inventories. Conservation groups' efforts to restrict development reduced the supply of private islands in the market, raising prices.
Southeast Asia has numerous islands, with Indonesia being an archipelago of 17,000 islands and the Philippines having around 7,100. Real estate laws restrict foreigners' ability to buy property in the geographical area, and many islands either have unclear ownership rights or are already settled. Private islands that are available in Southeast Asia's real estate market are also prohibitively costly due to being in high demand by hotel developers. Developments address these difficulties by selling private islands that have villas and neighbor islands that have high-end hotels; the proximity keeps costs of habitation down.
Europe has hundreds of thousands of islands many of which are privately owned. With 17,000 islands in Finland, 221,831 islands in Sweden and thousands in Croatia, Europe is increasingly becoming a hotspot for private island holidays. Many islands, although privately owned, are not suitable for development, due to legal and governmental restrictions or due to the physical characteristics of the island.
List of high profile island owners
* Gianni Agnelli, Estate of – Dino Island off the Calabria
- Pamela Anderson – Greece in The World, United Arab Emirates 
- Bacardi family – Near Grenada
- Marlon Brando – Tetiaroa, French Polynesia
* Sir Richard Branson – Necker Island & Moskito Island, British Virgin Islands; and Makepeace Island Australia.
- Raymond Burr – Naitoumba, Fiji
- Nicolas Cage – Leaf Cay, Bahamas
- David Copperfield – Musha Cay, Bahamas
- Edward de Bono – Green Island – Australia, Tessera – Italy, Reklusia – Bahamas.
- Johnny Depp – Little Hall’s Pond Cay,Bahamas. * Leonardo DiCaprio – Blackadore Caye, Belize
- Celine Dion – Île Gagnon, Quebec.
- Disney family – Echo Island, San Juan Islands, Washington, USA
- Du Pont family – Cherry Island, Chesapeake Bay, Maryland, USA
- Errol Flynn – Navy Island, Port Antonio, Jamaica
- Mel Gibson – Mago Island, Fiji
- Bear Grylls – St. Tudwal's Island West, Wales, UK
- Gene Hackman – Fawn Island, Washington State, USA
- Nick Hexum – Melody Key, Florida
- Faith Hill and Tim McGraw – Bahamas
- Dean Kamen – North Dumpling Island, New York, USA
- John Lennon – Dorinish Island in Clew Bay, County Mayo, Ireland
- Charles A. Lindbergh – Île Illiec, Brittany, France
- Ricky Martin – Angra dos Reis, Brazil
- Dietrich Mateschitz – Laucala, Fiji
- Eddie Murphy – Rooster Cay, Bahamas
- Peter Nygård – Nygard Cay, Bahamas
- Aristotle Onassis – Skorpios Island, Greece
- Michael Ondaatje – Several islands, Mahone Bay, Ireland
- Laurance Rockefeller – Sandy Cay, Jost Van Dyke BVI
- Cristiano Ronaldo – Deserta Island, in Ria Formosa, Portugal
- Diana Ross – Taino, French Polynesia
- Baron Rothschild – Bell Island, Bahamas
- Ted Turner – St. Phillips Island, South Carolina, USA
- Robin Williams – Pender Harbour, British Columbia, Canada 
- Desert island
- List of islands
- List of uninhabited regions
- Phantom island
- Principality of Sealand
- Category:Uninhabited islands
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