There are two separate ferry companies running ferries back and forth from Playa del Carmen to Cozumel. One ferry leaves 5 to 10 minutes ahead of the other one. Both ferries are more or less the same in comfort, speed and amenities.
It does not matter which ferry you take.
Both ferries have refreshments. You can get beer, pop and juices. The old ferry used to show reruns of old television shows on their televisions. The new ferry has televisions as well however, every time we have been on it, the televisions were off.
Ferry schedules change and each company produces its own published schedules [they are both different] which is why if you do a search on the net for Cozumel Ferry times you will get so many conflicting times.
We attempt to keep our schedule current, however, it can change without notice, so your best bet is if you are going to Cozumel/Playa del Carmen then simply get to the docks early and buy your ticket for the next available trip as soon as you get there, then sit and wait for the ferry.
PURCHASING YOUR TICKET
There are a number of different places where you can buy your ferry ticket. There are booths on 5th Ave. and more booths close to the docks. Each ferry company has its own booths and they try to out-sell each other.
To our knowledge the ferries are never completely sold out [except the early morning rides because of workers going to Cozumel] so you can always get a seat.
In Cozumel you buy a ticket at the dock where you board the ferry in San Miguel.