Keys Transportation provides private airport transfers to any destination in the Keys from either MIA or FLL. Prices start at $49 per person for transportation to Key Largo and get more expensive as you move south. Call or email for a price quote.
Greyhound Lines runs a special Keys shuttle twice a day (times depend on the day of the week) from Miami International Airport (departing from Concourse E, lower level) and stops throughout the Keys. Fares run from around $25 for Key Largo (MM 99.6) or Islamorada (Burger King, MM 82) to around $45 for Key West (3535 S. Roosevelt, Key West International Airport).
Keys Shuttle runs scheduled service six times a day in 15-passenger vans (9 passengers maximum) between Miami and Fort Lauderdale airports and Key West with stops throughout the Keys for $60 to $90 per person sharing rides.
SuperShuttle charges $191 for up to two passengers for trips to the Upper Keys; to go farther, you must book an entire 11-person van, which costs $402. For a trip to the airport, place your request 24 hours in advance.
Greyhound. 800/231–2222; www.greyhound.com.
Keys Shuttle. 1333 Overseas Hwy., Marathon, Florida, 33050. 888/765–9997; www.keysshuttle.com.
Keys Transportation. 305/395--0299; www.keystransportation.com.
SuperShuttle. SuperShuttle's blue vans are a saving grace at many Florida airports including Fort Lauderdale, Jacksonville, Miami, Orlando, St. Petersburg, and Tampa, Advantages include often cheaper fares than county-regulated cabs. On the downside, you might need to wait awhile for your van to fill up, unless you're traveling with a small group, and drop-offs may require multiple stops. Advance reservations are required, but depending on the city and slow circumstances the "advance" can be after you land. 800/258–3826; www.supershuttle.com.