If you look on the Bahia dive center website, they offer a Cozumel dive trip. I am not sure what the transportation is, but it may list that information.
I don’t know when we will start diving (I am going with my wife and kids, but my son is the only one that dives besides me). We plan on doing a few reef dives, a night dive, and a cenotes dive (I have never done one of those yet).