The Sea of Cortez is quite large. where are you planning on heading? San Carlos is very nice, there are several dive charters there but 2 major ones with there own large boats. You can head out to San Pedro Island and dive with the sea lions. There are tons of dive sites there. Just watch out the tidal surge can get very heavy. there is also rocky point (puerto Penasco) that is ok. You can also try and get to torguga island or see if anyone has a great white shark trip planned as well. It all depends on where in the sea of cortez you are wanting to head to.