Longboat Key is a barrier island and the coextensive town of the same name located on the central west coast of Florida in the United States of America. Longboat Key is south of Anna Maria Island, between Sarasota Bay and the Gulf of Mexico. It is almost equally divided between Manatee and Sarasota counties. The Town of Longboat Key was incorporated in 1955 as a municipality.
The United States Postal Service operates a Post Office on Longboat Key, with the entire island serviced within ZIP Code 34228. The post office was established on October 10, 1907, as Longbeach and was located in the community of that name on the north end of the key. On February 1, 1958, the name of the Longbeach post office was changed to Longboat Key. There was also a post office named Longboat established on March 27, 1914, in the Sarasota County portion of the key, but it was discontinued on January 14, 1922, and its functions were assumed by the Sarasota post office.
The quasi-governmental form of the Condominium Association exists in one of its most complex forms in and on Longboat Key, comprising the Federation of Longboat Key Condominiums. In addition to the Longboat Key Chamber of Commerce, and in concert with the Town of Longboat Key, these entities have made Longboat Key an exemplar of local government and citizen cooperation in participation and management for communities of its type.
Longboat Key is served by two newspapers, published year-round, the Longboat Observer and the Longboat Key News 
In recent years, "federalizing" the Key by having the U.S. Congress create the "Longboat Key National Seashore" has been suggested. Currently Longboat Key is located within two Florida counties, Manatee County in the north and Sarasota County in the south, but there have been calls for the Florida Legislature to pursue an initiative to create a 68th county, "Longboat Key County," to simplify governance of the island. Neither of these initiatives is likely to be passed, however.
The town's population was 7,603 at the 2000 census. As of 2004, the population of Longboat Key recorded by the U.S. Census Bureau is 7,622
.
According to the United States Census Bureau, the town has a total area of 17.1 square miles (44.2 km²), of which, 4.9 square miles (12.7 km²) of it is land and 12.1 square miles (31.5 km²) of it (71.18%) is water.
Some Longboat Key residents are "snowbirds," who vacation on or own second homes on Longboat Key, and are present only during the winter months. Others are homesteaders, utilizing the various homestead exemptions provided to Florida citizens who own and occupy their principal residences within the state, as set forth under the Florida Constitution.
There are numerous restaurants on Longboat Key, including The Dry Dock, the Longboat Key Club Restaurant, Cafe On the Bay, Euphemia Haye, Harry's, Columbia, Cork, The Bottle Shop, Moore's Stone Crab Restaurant, Mar Vista and The Old Salty Dog. There are also full-service grocery stores, including Publix, and pharmacies, located centrally.
Most of the Gulf side of Longboat Key comprises beaches.
Longboat Key is also home to the Longboat Key Club, developed by aluminum tycoon Arthur Vining Davis' Arvida Corp.. The Longboat Key Club is open to both visiting tourists and club members, and features indoor and outdoor restaurants, pool, resort buildings, golf courses, tennis courts and easy access to an adjacent gulfside beach.
Almost the entire land area of Longboat Key is now occupied. The remaining older, singly-owned houses are as much as 45 years old, annexed to comparatively small parcels, again an outgrowth of the 1/2 acre limitation on homestead property area within municipalities as set forth in the Florida Constitution. In the last few years, these properties have been purchased by new owners who sought to and did demolish them in order build small, ornate homes worth much more, many being valued to amounts on the order of as much as a few million dollars, a peculiar outgrowth of the unlimited-in-value homestead exemption for principal residences from forced sale provided to homesteaders under the Florida Constitution. This diverse mix of homes owned both singly and in condominium line the many cul-de-sacs and boulevards branching off main roads towards both the bay and the gulf, with the length of the island served by Gulf of Mexico Drive.
There were 4,280 households out of which 3.0% had children under the age of 18 living with them, 64.3% were married couples living together, 1.4% had a female householder with no husband present, and 33.5% were non-families. 30.2% of all households were made up of individuals and 21.6% had someone living alone who was 65 years of age or older. The average household size was 1.78 and the average family size was 2.11.
In the town the population was spread out with 2.6% under the age of 18, 0.9% from 18 to 24, 5.7% from 25 to 44, 32.4% from 45 to 64, and 58.3% who were 65 years of age or older. The median age was 68 years. For every 100 females there were 86.8 males. For every 100 females age 18 and over, there were 86.7 males.
The median income for a household in the town was $90,251, and the median income for a family was $107,983. Males had a median income of $61,157 versus $30,104 for females. The per capita income for the town was $80,963. About 1.4% of families and 2.9% of the population were below the poverty line, including 1.9% of those under age 18 and 2.0% of those age 65 or over.