The latest bus back from MK was on the schedule for 9:30. Not sure if they ran later or not. All ashore for KeyWest was 7:30 am with all aboard at 12:45. We docked at the Navy pier and were taken via trolley or train to the Mallory Square area. Our trolley driver told us to be back for the trolley to the ship no later than 12:15. I'd love to do the flight over to the Tortugas but felt it wasn't enough time to be worth it. At best you'd have 5 hours total.