At the northernmost end of the keys, within sight of Miami, is Biscayne National Park.  Protecting 4 diverse eco-systems including miles of mysterious mangrove forest along the mainland shore and one of the world’s longest living coral reefs, the park is an important haven for a number of water birds including Brown Pelican and White Ibis.  Most visitors arrive by boat to fish, snorkel or simply cruise.  Further information about the park can be found at the Visitor Centre located at Convoy Point, where there are also nature talks and ranger-led tours.  The Park also boasts an underwater “Shipwreck Trail”, exploring the remains of five distinct wrecks

Elliott Key is the park's largest island, rising from the remains of an old coral reef.  The first view of the island is characterized by dense mangroves but inland, visitors may be surprised to see a variety of more tropical trees such as mahogany and satinleaf, not found anywhere else in the United States.  The area is also rich in culture, once home to the Tequesta Native Americans before the arrival of the first European homesteaders.

A tropical forest rises from the remains of an ancient coral reef in the Lignumvitae Key Botanical State Park, near Islamorada in the Upper Keys. Although only accessible by boat, the island boasts the highest point above sea level within the Keys and a visitor centre from where there are regular ranger-led tours of the rare hardwood forest.

John Pennekamp Coral Reef State Park was the first underwater park in America, protecting an extensive coral reef which, today, can be best viewed from the ‘Spirit of Pennekamp’ glass-bottom boat.  The visitor centre boasts a large saltwater aquarium and there are nature walks and kayak trails.

Christened "Cayo Vivora" or Rattlesnake Key by the Spanish due to its shape, Long Key was once the site of a luxurious fishing resort.  Although this was destroyed by a hurricane in 1935, visitors can still discover the attractions of this island by canoeing through a chain of lagoons or following the Golden Orb Nature Trail on-land.

Big Pine Key, famous for its pine woods and natural habitat for the small white-tailed deer, can only be accessed by boat and is protected by the National Key Deer Refuge.

The Crocodile Lake National Wildlife Refuge, established to protect the breeding habitat of the threatened American Crocodile is located on Key Largo.  Currently closed to the public, the reserve also protects the natural habitat vital for the survival of native creatures such as the Key Largo woodrat, Key Largo cotton mouse and the Eastern indigo snake.

Visitors to Marathon Key are encouraged to hire a kayak and take to the water to discover the coral reefs.  Local wildlife includes 5 foot sharks and barracudas as well as herons and sea turtles.

Key West’s attractions include the home of Ernest Hemingway and the Secret Garden of eco-artist Nancy Forrester.  But this is also home to the Key West National Wildlife Reserve.  Managed by the National Key Deer Refuge, the reserve includes mangrove islands, sand flats and sand dunes - protected habitats for sea turtles and wading birds. The reserve can only be reached by sea and there are a number of commercial companies offering excursions and boat tours of the area.  Although two of the reserve’s islands (Woman Key and Boca Grande Key) have beaches closed to the public, the remainder of the beaches are open to birdwatchers, photographers and educational visits whilst the surrounding waters are ideal for fishing and diving.  The Florida Keys Eco-Discovery Centre is also based in Key West, an interactive museum offering a range of interesting and educative exhibits on native plants and animals. 

Catamaran tours from Key West tour the surrounding sand spits, coral reefs and the uninhabited island of Boca Grande.  The warm waters here are teeming with marine life including dolphins, sharks, manatees and sea turtles.

70 miles west of Key West lies a cluster of seven islands called the Dry Tortugas, accessible only by boat or sea-plane. These, along with the surrounding waters, form the Dry Tortugas National Park, a remote area renowned for its bird and marine life.  Visitors come here to snorkel, fish or just admire the view.  Here, on Garden Key, is Fort Jefferson, a deserted red brick structure which poses a striking contrast to the bordering white sands and azure waters.  Designated a National Monument in 1938, the fort can be explored with a ranger or a self-guided tour from the Visitor Centre.  The surrounding waters offer excellent snorkeling or diving opportunities.  One of the most impressive diving sites is the Windjammer Wreck, less than 1 mile from Loggerhead Key.  This once magnificent sailing ship was blown onto the treacherous Loggerhead Reef by strong gales in 1907 and is now home to a wide variety of fish, coral and marine life.