We had a similar situation although a hotel was supplied by RCI for the day in the vicinity of Miami airport
I see no reason why you could not arrange this yourselves
We spent a few hours in the Dolphin shopping mall which is reasonably close to the airport and passed a bit of time (some good prices as well!)
Obviously if you do get a day room and the weather is nice you could lie in the sun
Before booking a hotel check with your travel agent it maybe you will get this day room option as part of your cruise cost. There is sometime an option to do a coach tour of the area before being dropped off at the airport probably around 2/3 p.m., but that still leaves you a few hours before check-in.
If you have booked the flights with the cruise line they tend to take you to the airport at 9.30 and dump you there. There may be a tour that takes you round the sights and drops you at the airport around 2/3pm. Check on the website. Alternatively - do your own thing and hire a car, drive out to one of the Malls or to the beach and have a nice relaxing last day.
Yes, this is feasible but a hotel room for the day can be $45+ you will have to get there and then get to the airport afterwards so why not rent a car either from Fort L airport or there's one close by the port in 17 SE Street near the Renaissance hotel. Arrange with them to drop it off at Miami Airport and pile your luggage into it. Drive to a beach hotel or any hotel, a mall, or the airboat rides and enjoy yourselves for the day. It may be worth checking with who'ever you cruise with to see wether they make any arrangements, that you will have to pay for, on disembarkation day. Hope that helps. .... Neil.
We have been able to book shopping and a tour on board, for the day, then the bus took us to the airport. we did the everglades, shopping mall, beach etc. it was a really nice last day.