Second homes: Easy access to nature, watersports in Florida's Upper Keys

— -- The Florida Keys are about as far south as you can get in the Lower 48, but for second-home owners, their appeal has more to do with how far removed they are from contemporary culture. Yet they are still close in terms of convenience, within an hour of Miami and its busy international airport.

The Keys are a chain of islands beginning just off the tip of southern mainland Florida and curling southwest for 106 miles. The upper half, which is more popular with second-home owners, is characterized by pristine nature, watersports and easy road access from South Florida. The lower half is dominated by Key West, the largest, most touristy, most developed Keys destination.

The three Upper Keys are Key Largo; Islamorada, which comprises six major islands; and Marathon, which has more than a dozen islands. Though some waterfront mansions here rank among the nation's priciest, inland condos in Key Largo begin around $150,000, says real estate agent Russell Post of Russell Post Sotheby's International Realty. Islamorada is a bit less expensive, and Marathon is even less.

For fishing, Islamorada and Marathon are tops. Though Key Largo lags slightly, it is one of the world's top dive destinations and home to the Florida Keys National Marine Sanctuary and John Pennekamp Coral Reef State Park. Bordering Everglades National Park, Key Largo is also a popular birding, sea kayaking and eco-tourism destination and has the most restaurants, bars and hotels in the Upper Keys.

"A lot of Floridians look at Key Largo the way Bostonians look at Cape Cod: as a place for weekend and summer homes," Post says. The majority of second-home owners live within driving distance or come from the Northeast. The exception is the Ocean Reef Club on Key Largo, the largest and most expensive development, which has its own private airport and attracts owners from around the world.

The first phase of a $300 million improvement to the 18-mile stretch that connects Key Largo to the mainland opened this month. The entire project is scheduled for completion in 2011 and should make all the Keys even more accessible.