{For those coming from Tampa Bay there is a charter airline called SeaCoast that departs from St Pete and on request from Zephyrhills to Key West.  It is $99 each way and are 10 seater planes (including the pilot).  It is an 80 minute flight at 7,000 feet.  It is a much cheaper alternative to flying out of Tampa with Continental.  The other added plus is no TSA on either end.}

 

 

Update - January 2016:  SeaCoast Airlines terminated operations completely in 2012.  It no longer operates and there are no longer flghts to Key West.  Southwest Airlines, which was also a half-price option to that of Continental, also terminated services to Key West in 2014.  The locals are lobbying with Southwest to re-consider their Service to the island. Those airlines that currently fly into Key West, originating from Miami International Airport, are U.S. Air, American Eagle, British Air and Delta. The least expensive at the time of this writing, with a great deal of advance reservation, is American Eagle (actually Republic operating as American Eagle) at a cost of $257 roundtrip.

 A ferry boat service between Marco Island / Ft. Meyers, FL and Key West is available through Key West Express at a cost of $124-$139 with 8-day advance purchase, or $159 without advance purchase. Weather & marine conditions may influence your duration of travel. There is a parking charge of $12 per day at the dock lot. You are allowed two small bags per passenger.  You may also bring a non-motorized bicycle for an additional $18 charge.  

 The ferry boat option reduces the travel time from about 6 – 7 hours true drive time down to around 4 hours including boarding.