Cayo Costa was occupied by Calusa people until about 1700. Native Americans built a number of shell mounds on the island. Starting early in the 18th century, fishermen from Cuba began establishing ranchos, stations for catching and processing fish for the Havana market, along the southwest coast of the Florida peninsula from Tampa Bay to the Caloosahatchee River, possibibly including on Cayo Costa. The ranchos operated through the period of British rule, the second period of Spanish rule, and into the period of American rule, until they were forced out during the Second Seminole War. Tervio Padilla, commonly known as "Captain Pappy", settled on Cayo Costa in the second half of the 19th century. Born in the Canary Islands, Padilla became a U. S. citizen in 1862, while a resident of Key West. Padilla operated a rancho on Cayo Costa, where he and his workers caught and processed fish for the Cuban market. A cemetery on the island holds the graves of Padilla and his wife, as well as of approximately 30 Cuban fishermen who died in a 1910 hurricane.
There is a variety of wildlife that can be seen at the park. Among the most looked-for animals found in Cayo Costa State Park are the sea turtles. There are four species found on the island, the loggerhead, hawksbill, green, and Kemp's ridley. Cayo Costa has many volunteers who check the entire nine milebeach each morning during sea turtlenesting season to find new nests and document them which is during the months of March through October in Southwest Florida. The loggerhead turtle is found far more than the others, and the green turtle is a distant second. The loggerhead turtle and green turtle's eggs have the most diverse niches awhile hawksbill and Kemp's ridley do not. Their niches rely on climate and weather which allow the eggs to survive on land and eventually hatch. Cayo Casta State Park is a major nesting site for turtle nesting in Florida. These nests are protected by Florida State Parks and are regulated by volunteers and staff. The nests are patrolled and marked off so that guests can avoid interrupting them. Another species found on the island is the common raccoon. These animals pose a big problem during the sea turtle nesting season due to the fact that they are the most common species of predation on the eggs. Others types of predation on the eggs include: high tide, foxes, ants, ghost crabs, and looting humans. The West Indian manatee is also found coming up to the island beaches. This is considered an endangered animal, but the population is currently growing. They can be seen from the beach or near the canals and docks of the island. The West Indian manatee is found in Florida and Puerto Rico. Although they are part of the same species, there is genetic diversity and allele frequency between the two populations. The bottlenose dolphin can also be seen jumping, swimming, and playing along the all nine miles of beaches on the island. Each dolphin has its own personal whistle just like any human would have a distinct voice. Dolphins are able to recognize these sounds and communicate through them. Scientists are able to measure these sounds and put them with the individual dolphin that made them. The snowy egret can be found on the island. They usually stay near the beaches. They are a small white heron with long, slender black legs and yellow feet. Both sexes of the snowy egret have the same features even during the breeding season. The southern bald eagle can be found flying about the island or sitting up on the high trees. This is another threatened species. The eagles eat a variety of animals, but prefer fish. They scavenge and steal food when they are able to, and the eagle hunts for live prey only as a last resort.
Flora
The mother-in-law's tongue is found on the island. This plant is most commonly seen as a house plant, but this invasive species came from one of the houses on the island and has spread widely. Staff is currently trying to rid the island of this invasive plant. The resurrection fern is found growing on trees throughout Cayo Costa. It is an epiphyte that if it is dehydrated, will turn brown and curl up its leaves looking dead. When the plant receives water or rain, the plant will "come back to life" and reappear green and alive. Seagrape is found at Cayo Costa. The fruit comes about in the summer time during the wet season of southwest Florida. It starts out at a bright green grape then ripens to a purplish color. The fruit mainly consists of a large seed with little flesh. It is well known of Florida natives to make jellies or wines from the grapes. This plant is native to South Florida and the Caribbean. This plant can grow up to fifty feet tall, and is usually close to the ocean because they are one of the few salt tolerant plants.
Amenities include boat slips, beaches, hiking trails, picnic pavilions, 12 primitive camping cabins and bath house/restrooms. The park offers a small nature center/gift shop with nature exhibits as well as items for sale. The park has the following available for purchase: ice, sun lotion, bug spray, T-shirts, hats, bird keys, shell keys, and postcards. Cayo Costa has bikes available for half-day and full-day rentals.
Camping
There are 12 primitive cabins and 30 tent sites available for camping each with its own picnic table and fire pit/ground grill assigned to each site. Boat slips are available for those who wish to camp aboard their boats.
