Getting to the ship is easy, once you have parked in the parking garage across the street. Just a short walk and you are at the boarding dock, pictured below:
The picture below is from one of the may shore excursions you can purchase for Cozumel.
Below is the Carnival Cruise docked in Cozumel Mexico. Towards the evening, the ship will head out back to Tampa Florida. Note: When you leave – It isn’t an overnight trip, you’ll have a whole day at sea, before reaching Florida.