Here is the part every other Carnaval page leaves out, and it is going to save some of you a wasted booking.
The parades start at 6:00 PM. A typical Cozumel all aboard is between 4:30 and 5:30 PM. Do the subtraction: on a standard port call you will be back on the ship, or sprinting for it, before the first float moves. It does not matter that your ship is docked on February 7. You still will not see the parade.
This matters more here than almost anywhere, because Cozumel takes roughly two thirds of every cruise passenger who visits Mexico, and Carnaval lands square in the middle of peak cruise season. So a lot of people are booking February sailings specifically for this, and nobody is telling them the times do not line up.
There are exactly three ways it works. One, your ship has an overnight call or a late departure, which a handful of itineraries do, so check your specific sailing rather than assuming. Two, you fly in and stay on the island for a few nights, which is the honest answer for anyone who actually cares about seeing Carnaval. Three, you catch the daytime edges instead: the town is decorated all week, the pre parade staging along Melgar in the late afternoon is genuinely fun to walk through, and the atmosphere in San Miguel during Carnaval week beats a normal port day comfortably.
If you are working out your port day around this, our cruise port guide covers which pier you dock at and how the all aboard clock really works, and the excursion guide has the risk table for anything you book alongside it.