Yes, we used to go on a Saturday morning and return Sunday but then the boat is just an hour from our house. Most folks might go down on a Thursday or Friday, some even staying the week. I see they have changed the schedule, leaving both Miami and Key West later.

Be sure to check the website for the most current time and rate info! Just pulled the following off their site. It is subject to change.
http://www.seakeywestexpress.com/

Fares from Miami to Key West
Miami Fares inclusive of all charges
Adults
$102.00 per person round trip

One way $51.00

Juniors
Juniors up to 12 years
$70.00 round Trip

One way $51.00

Seniors - 62+
Seniors - $83.00 round trip

One way $51.00

College Students
with current ID
$83.00 round trip

All one way fares between Miami and Key West are $51.00

Depart Miami 10:00am Arrive Key West 2:00pm Depart Key West 7:00pm Arrive Miami 11:00pm

its leave miami at 8:30 am - get in at 12:30 pm.......and go out on the water for sesssion!

and i belive 5:30 pm leaves key west

That is the schedule that we followed the times I went down. They have changed it though to a 10 am Miami departure arriving at Key West at 2 pm. I confirmed this by phone before putting it up in this post. The boozers must have been complaining about leaving Miami too early?! The good news is that you get to leave Key West an hour and a half later though at 7 pm.

Same Ferry from Naples?
 

Someone mentioned the same kind of ferry or same company not sure wich, but could you post their websight and prices leaving from Naples to the Keys.

Thanks